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Title: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 13, 2011, 04:14:37 PM I was running short on 4 pin molex plugs on my PSU. Going through my box of cables I came across a single 4 pin molex to 6 pin PCI-E connector. Just what I needed to get around my shortage. So I did some math
4 pin Molex is rated for 60W, compared to 75W for PCI-E. Motherboards supply up 75W. One PCI-E connector is a proper one, 75W One 4 pin to 6 pin: 60W 75+75+60=210W. SHould be plenty for a 5850, even with a decent overclock no? Nope. After one day: http://img254.imageshack.us/img254/6445/img036u.jpg (http://imageshack.us/photo/my-images/254/img036u.jpg/) I massacred the cable by pulling it out, but there were and still are clear burnmarks. Dont skimp on this folks, its not worth burning your house down over a cable :) Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: likuidxd on November 13, 2011, 04:18:26 PM Not positive, but I don't think they make these anymore for this reason. The standard now uses power drawn from two molex powers to one PCIe 6 pin.
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 13, 2011, 04:22:56 PM I dont remember where I got that cable from. It was never used, still in plastic wrapping. I think it came with an old nvidia card (8800gt or so? or perhaps a card that draws only ~75W ).
Anyway, just wanted to show you shouldnt use them for a reason :). I was surprised though, you'd think there is some safety margin on those specs, and 60W to 75W isnt that much a difference. From now on Ill see those 8 pin PCI-E connectors as a selling point. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: plastic.elastic on November 14, 2011, 05:09:03 AM I dont remember where I got that cable from. It was never used, still in plastic wrapping. I think it came with an old nvidia card (8800gt or so? or perhaps a card that draws only ~75W ). Anyway, just wanted to show you shouldnt use them for a reason :). I was surprised though, you'd think there is some safety margin on those specs, and 60W to 75W isnt that much a difference. From now on Ill see those 8 pin PCI-E connectors as a selling point. Does not make sense, its an isolated case with a bad connector. I'm using several connectors like this (provided with Sapphire 5850) and all works flawless. 5850 cant draw that much power. Your calculation shows more than what it needs. Edit: i notice something odd with your connector. The 6pin misses the middle 12v wires? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 08:03:52 AM Does not make sense, its an isolated case with a bad connector. I'm using several connectors like this (provided with Sapphire 5850) and all works flawless. Id have a good look at them, particularly if you are overclocking (I was testing at 900 MHz but only since a few hours and at stock voltage). Quote 5850 cant draw that much power. Your calculation shows more than what it needs. Well, I would have more faith in a brown melting wire than my "calculations" :). As it turns out, these cards usually only draw ~25-30W from the motherboard. That leaves ~120W for those 2 connectors at stock speed. Assuming the card pulls from each plug equally, thats the limit of the 4 pin molex spec at stock speed. Quote Edit: i notice something odd with your connector. The 6pin misses the middle 12v wires? Do you have 3 yellow wires on your plug? To be clear, this is a SINGLE molex to PCI-E adapter. Most (all?) new cards come with dual molex to PCI-E. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: sadpandatech on November 14, 2011, 01:13:14 PM Edit: i notice something odd with your connector. The 6pin misses the middle 12v wires? Do you have 3 yellow wires on your plug? To be clear, this is a SINGLE molex to PCI-E adapter. Most (all?) new cards come with dual molex to PCI-E. All of my official sapphire plugs have all 3 yellow wires there. And of course are dual molex. I've got a few old pci-e 6 pin that are lakcing the middle yellow that came with older 8x, 9x nvidia cards as well. Not so sure it woulda helped much in your situation but its probably not healthy if the card is looking to spred that draw over 3 pins on the card side is all. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 01:22:34 PM All of my official sapphire plugs have all 3 yellow wires there. And of course are dual molex. Well, thats kind of my point. With dual molex you should be fine, its the single molex to PCIE cable that is a fire hazard. Not sure if there are 3 wire variants for single molex, but since the limitation is the connector rather than the wires (and the pastic connector has brown burn marks), I dont think it would improve much. Not going to touch single molex to PCIe anymore even if there are a dozen wires :). Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 14, 2011, 02:41:23 PM That connector is all kinds of weirdness. Can't believe anyone actually authorized that.
Worse is the fact that even IF the Molex connector could handle the current the PCIe 6-pin isn't rate even for 60W in a configuration like that. The PCIE 6-pin is rated for 72W @12V = 6.24A. This is spread across 3 power lines for 2.08A each. With only 2 of the 3 12V connectors attached even at only 60W those leads are pulling 2.5A a piece If you want to see the glass half full ... had the Molex side of connector not burnt likely it could have destroyed your graphics card. Honestly whoever made that connector should be sued and if it was included with a GPU whoever included it should be sued too. Standards exist for a reason. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 03:42:16 PM Hmmm.. now you make me nervous. I just went through my box of cables, and I have plenty of those. Like this one, its a dual molex to PCIe, but also has only 2 red and 2 yellow wires:
http://s9.postimage.org/p3gg2d7an/IMG041.jpg If I remember correctly, that cable actually came with my 5870? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 14, 2011, 03:49:24 PM Sorry for the scare. I went back and looked at the standard.
It looks like the 6pin connector does allow the middle connector to be unconnected. However that increases the amperage on remaining two wires to 3.125A (max). Why they hell they allowed that I don't know but I assume if the standard allows it then all components must be rated/tested to handle up to 3.125A per line. Here is an example of a different way to connect them: http://www.playtool.com/pages/psuconnectors/pcie6.jpg I guess looking at it further there really is no good way to connect 6pin to dual molex. Dual molex gives you 4x grounds but only 2x 12V. So while the middle connector above it is connected it is done by connecting two pins to a single molex pin. That means the amperage on each of the 6pin connectors is <2.1A but one MOLEX is pulling 4.2A while the other is pulling 2.1A. That isn't exactly optimal either but I would rather have lower load on the PCIe leads and more importantly the traces on video card connector. Good news is as more and more PCIe capable power supplies are sold it likely is less and less of an issue. Somewhat off topic: For the record I hate when companies use nonstandard wiring. Why use red wires (as seen in your photo)? Did they have left over red wire to they used that instead of 4 black wires? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 04:00:22 PM Im guessing they are pulling from 12 and 5v? 2 wires with 12v (yellow) and two from 5v (red) ? WHich wouldnt be a bad idea for old PSUs that likely have ample 5V power (and not enough on 12v)
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: sadpandatech on November 14, 2011, 04:01:59 PM Still even if it is ok it makes me wonder WHY do it? Why push >3.125A per wire when you can have enough connectors (both on PCIe side and on dual Molex side) to keep current below <2.1A? because capitalism rules! 10k units x 2" 16Ga wrapped copper wire @.08 to .38 per ft. = profits Edit; which is why sapphite cheats on their's. It is more dangerous to the traces on the board than to the 16ga wire. Sapphire takes advantage of this with the cables I got from them by only running 2 12v lines form the molex and then using a 1/2" wire to fill the middle pin from one of the other 2 at the 6 pin connector... Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 04:05:57 PM here is the entire cable:
http://s9.postimage.org/v73kqaxbf/IMG042.jpg (http://postimage.org/image/v73kqaxbf/) Ive only seen one's like that TBH. Well, in so far I paid attention. Ill check my mining rig later. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 14, 2011, 04:05:59 PM Im guessing they are pulling from 12 and 5v? 2 wires with 12v (yellow) and two from 5v (red) ? WHich wouldnt be a bad idea for old PSUs that likely have ample 5V power (and not enough on 12v) No they can't be. That wouldn't work. Can't supply 12V from a 5V lead without using some sort of converter (VRM, DC to DC switching,etc). Looking at the connector the red wire (which does denote 5V) is actually connected to pin2 = ground. On 1) 12V (usually yellow) 2) ground (usually black) 3) ground (usually black) 4) 5V (usually red) So they are connecting ground to ground however they decided it would be fun to use red wiring instead of black. Maybe they have 10,000ft of spare red wiring to get rid of? Still annoying IMHO (and a pet peeve of mine). Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 04:06:29 PM see picture above.
edit: oops you are right. I thought that 2/3 molex pin was 5v, but its ground. Why would you have 4 ground wires and 2 current carrying? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: cicada on November 14, 2011, 04:13:18 PM Funny, every single card I bought ~4 mo ago came with single molex to 6-pin adapters. I was using probably 8 of these amongst my various rigs and never had an issue - the wires and connectors were never even warm. The build quality seems superior to the one P4man posted, but still - why would they supply only single-molex connectors if this was a such a major risk?
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: sadpandatech on November 14, 2011, 04:14:50 PM see picture above. edit: oops you are right. I thought that 2/3 molex pin was 5v, but its ground. Why would you have 4 ground wires and 2 current carrying? Its supposed to be 3 and 3. 2 of the ground wires join together at the center pin on the 6 pin connecter. Edit; likely they split that ground like that to compensate for any extra resistance that may be on one of the psu molex lines. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: plastic.elastic on November 14, 2011, 04:30:20 PM All of my official sapphire plugs have all 3 yellow wires there. And of course are dual molex. Well, thats kind of my point. With dual molex you should be fine, its the single molex to PCIE cable that is a fire hazard. Not sure if there are 3 wire variants for single molex, but since the limitation is the connector rather than the wires (and the pastic connector has brown burn marks), I dont think it would improve much. Not going to touch single molex to PCIe anymore even if there are a dozen wires :). Nope, all the connectors come with Sapphire xtreme are single molex. I believe many others also use them. They have 2 12v wires from the 4pin and convert into 3 wires at the 6pin. This just shows your connectors are poorly made. Has nothing to do with single molex, i overclock my cards as well. The 5850 realistically draws 150w Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 14, 2011, 04:37:38 PM Just went to check what I had on my rat rig. DeathAndTaxes, you are going to love this one.
http://s12.postimage.org/6zz8w0a55/IMG044.jpg (http://postimage.org/image/6zz8w0a55/) Yep. BROWN cables :). Same layout as the other splitters though. I just checked if they felt hot, and they werent. Cables seem cool enough As an aside, this is the entire rat rig now; http://s12.postimage.org/6bqed2bfd/IMG048.jpg (http://postimage.org/image/6bqed2bfd/) DnT, you will love the blue/red fan extension cables! :D. Ans yes, Im using 2 PSUs now. Didnt trust the antec 500W to power 5870@1Ghz + 5850 @900 Mhz + old P4 prescott cpu (yes, I know). It managed fine at stock speeds, but thought Id not push my luck, so I recycled an old 450W unit with a faulty fan, hotglued a spare fan on it. Its a rat rig after all Dont ask about power efficienciy, its not efficient, but hey, it works, and it does a good job keeping the storage room from freezing :) Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: m3sSh3aD on November 15, 2011, 11:01:37 AM I just had a 6870 and 6950 replacements for old XFX junk and one came with single, one came with double power molex. Using the 3V line for your VGA cards isnt the wisest idea either. 12V rail/rails are there for a reason. 2 good 700-800 is better on a 4 card system than a 1200W with 3 PCI express that has to use a 3V for the 4th card.
Never experienced this but i never experience a Motherboard sending load beck through the GROUND to te PSU and killing itself and NEARLY the PSU at the same time. I use the PSU just to power the VGA cards now as the mobo connector is burnt to a crisp!!! Gigabyte are S**T, and so are XFX, be warned Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: plastic.elastic on November 16, 2011, 02:39:06 AM I just had a 6870 and 6950 replacements for old XFX junk and one came with single, one came with double power molex. Using the 3V line for your VGA cards isnt the wisest idea either. 12V rail/rails are there for a reason. 2 good 700-800 is better on a 4 card system than a 1200W with 3 PCI express that has to use a 3V for the 4th card. Never experienced this but i never experience a Motherboard sending load beck through the GROUND to te PSU and killing itself and NEARLY the PSU at the same time. I use the PSU just to power the VGA cards now as the mobo connector is burnt to a crisp!!! Gigabyte are S**T, and so are XFX, be warned what the heck are you talking about? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 16, 2011, 02:49:33 AM Nobody knows. No videocard is powered by 3V so the post doesn't even make sense.
Quote Using the 3V line for your VGA cards isnt the wisest idea either. Well it is little more than unwise, it is impossible. Did you accidentally try to plug this into the video card? It is the only connector on ATX powersupply which has 3V. ;D http://www.playtool.com/pages/psuconnectors/main24pin.jpg Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: sadpandatech on November 16, 2011, 03:03:10 AM I believe Mess was refering to the miscolored cables in post #'s 1, 9 and 13...
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 16, 2011, 07:21:26 AM I believe Mess was refering to the miscolored cables in post #'s 1, 9 and 13... None of which show 3V being used. Only 12V and ground. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: m3sSh3aD on November 16, 2011, 10:48:31 AM I believe Mess was refering to the miscolored cables in post #'s 1, 9 and 13... None of which show 3V being used. Only 12V and ground. Well, I am on about them cables that plug into the 4 pin molex power connector. One card came with a single 4-pin to 6pin VGA, and the other had TWO 4-pin power molex's to 6-pin, so my point there is they STILL SUPPLY BOTH TYPES! Whats that 3.3 and 5V on my power supplies then? AKASA HCP 1200W - +3.3V 25amp & +5V 25amp which combined Max out @ 175W then 8x 12V 30amp rails which max out @ 1198 99Amps. If im not wrong the 4 pin molex and SATA power connectors all use either the 3.3V or the 5V. SO connecting a VGA card to the 4-pin molex doesnt run it through ANY of the 12V rails. Simalar situation i have on a OCZ 750W, Another AKASA AK1200 and so on. Unless im mistaken and the 4 pins are powered from the 12V rails. This im not 100% certain, More of a presumption in all honesty as i don’t see why you would run sata & 4 pin off the 12V rail???? They really require 12Vs? Correct me if im wrong, im sure you will :) Just something ive always thought and kept with proper connectors and skipped the converters COMPLETELY. Never liked the look of them :)PSU's are not my strong point, Only recently had to play around with multi PSU's and blown cheap PSU's at the start :) They provide power and corsair AX series and AKASA HCP are at the top of the pile(but not cheap) Thats all i need to know about PSU's :) Corsair have a slightly better SINGLE rail design with the AX1200. I got a feeling im wrong on this but i just woke up and can't be bothered look. I'm sure you 2 will inform me what the 3.3 and 5V are for. I'm guessing the motherboard and its not passed through the 4-pin molex's power. I've kinda got bored of arguing with you 2, Never thought that would happen haha. Putting my neck on a guillotine as well with this PSU thing, persumtion is the mother of all F**K UPS :) Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 16, 2011, 10:55:01 AM Correct me if im wrong, You are wrong. IN the time you typed all that surely you could have googled pinouts http://www.marnscda.com/Guide/Conector.jpg Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 16, 2011, 02:00:12 PM P4Man:
Thanks for the image. Nice visual summary. Hint: to m3sSh3aD 1) The only 3V connection on any ATX power supply is in the 24pin MB connector. The aux connector P4 showed above has been removed from the latest spec because MB honestly no longer needs 3V/5V. The 3V and 5V pins on MB 24pin connector are also rarely used. They just exist because at one time the CPU was powered by 3V and most of the MB logic by 5V. However over time the power demands of CPU made that non-viable so CPU/MB/RAM are powered by 12V connector. The VRM on motherboard step that down to the voltage required by all the components. 2) Even if the Peripheral connector (often called MOLEX connector) had a 3V (or 5V, or 7V, or 120V, or 24V, or 18.2V) connection you couldn't use it to power a 12V device. If somehow you needed to power 12V GPU w/ a 3V rail you would need to use some device like a transformer to convert the 3V -> 12V. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: m3sSh3aD on November 16, 2011, 04:31:18 PM Learn something new everyday. Cheers. Never had to look into it that far. I still dont like them adapters. Prefer have them direct PSU, just me. I got out of tech a decade ago, Excuse me for being a bit behind on this and that but that is something ive never actually checked, Ever haha :)
Maybe you could explain this.... http://imageshack.us/photo/my-images/841/imag0078bo.jpg/ i blame gigabyte, The Akasa PSU is still runnint 4 cards soundly. But im informed thats the ground!!! Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 16, 2011, 04:39:00 PM Learn something new everyday. Cheers. Never had to look into it that far. I still dont like them adapters. Prefer have them direct PSU, just me. I got out of tech a decade ago, Excuse me for being a bit behind on this and that but that is something ive never actually checked, Ever haha :) Maybe you could explain this.... http://imageshack.us/photo/my-images/841/imag0078bo.jpg/ It looks like the most damage is on pin #10 which is 12V connector. Likely supplying power to PCIe slots. What were the 4 cards? Powered extenders? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: m3sSh3aD on November 16, 2011, 04:43:27 PM Learn something new everyday. Cheers. Never had to look into it that far. I still dont like them adapters. Prefer have them direct PSU, just me. I got out of tech a decade ago, Excuse me for being a bit behind on this and that but that is something ive never actually checked, Ever haha :) Maybe you could explain this.... http://imageshack.us/photo/my-images/841/imag0078bo.jpg/ It looks like the most damage is on pin #10 which is 12V connector. Likely supplying power to PCIe slots. What were the 4 cards? Powered extenders? 4 cards, 1 card on a powered extender. so 3x75=225 through PCIE, surely not enough to cause that. 5850's. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: cicada on November 16, 2011, 04:48:15 PM The Akasa PSU is still runnint 4 cards soundly. Please tell me you're not using that blown 24pin ATX connector to power another board? The damage on the board looks like a short, considering the plastic around the pin of your PSU's connector seems to have been left behind. It would appear that something connected your 12V rail to ground at low resistance.. stray wire around your PCI-e ports or something similar. If you're still using that PSU with the busted connector.. stop. That's just asking to start a fire and/or destroy another board. [edit] I suppose if you're using it to only power the 4 cards directly, and not using that 24pin connector it's probably ok, as long as no +V got got spot-welded to a G when it blew :) Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on November 16, 2011, 04:53:46 PM 4 cards, 1 card on a powered extender. so 3x75=225 through PCIE, surely not enough to cause that. 5850's. Well 225W would definitely cause that but no card pulls the max from PCIe slot. While the slot *CAN* support 75W even 5970s pulls ~30W at peak load (remember that is for 2x GPU) from the PCIe slot. The rest comes from the power connectors. Which cards were they, just curious. The reality is most MB manufacturers aren't going to design their board to handle 7x75W just because it has 7 PCIe slots. Maybe they should but they don't because outside of us insane miner's nobody loads a MB like that. MB companies cut corners figuring x watts is enough. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: m3sSh3aD on November 16, 2011, 06:27:02 PM just sapphire 5850 xtremes
Crazy issue Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 16, 2011, 07:24:09 PM Maybe you could explain this.... http://imageshack.us/photo/my-images/841/imag0078bo.jpg/ Any decent PSU should have short circuit protection, so Im not sure thats it. Just a wild guess, Ive had a motherboard where that 4 pin ATX connector doesnt lock in to place. The "lid" is only in the middle and locks the 20 pins, but not the extra 4 pin if you PSU has a 20+4 pin connector like that. If its not securely put in place, it could loosen itself and bad things might happen. Actually just a few days ago I pretty much had that exact issue only with a 4 pin cpu connector loosening itself (PSU has 2x4 pin for CPU, motherboard only 1x4 pin, and both PSU leads fit, and work, but only one "clicks". I had used the wrong one). Out of the blue my computer shut down and would no longer boot. Turns out that connector came came lose. Luckily nothing was damaged, but I imagine had it been pulling 20+A and release slowly, it could have turned in to a lightshow. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: cicada on November 16, 2011, 07:51:01 PM If its not securely put in place, it could loosen itself and bad things might happen. Appears the majority of the damage happened on the edge of the 20pin connector. It also looks like the plastic shroud around the pin got left behind in the motherboard header, though it's hard to tell from the blurrycam. It doesn't seem like coming-loose caused it. I tried to find some info on those Akasa PSUs, they seem to be good little buggers, and definitely have short-circuit protection, so that's also unlikely. With only 4 cards, and only 3 possibly pulling from the ATX header directly, the only thing that makes sense to me is a serious voltage sag. If the 12V rail somehow dipped way under spec, the current needed to compensate would have increased greatly, which could definitely lead to this kind of failure while possibly missing the short-circuit protection. That kind of thing doesn't normally happen without really excessive draw though, so this is a bit of a mystery. [edit] This thread got way off track ;) P4man, the same kind of thing could blow the pins in a 4pin molex connector for the same reason, have you measured the voltage on your 12V rails to see if you've got bad sag? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on November 16, 2011, 08:01:33 PM [edit] This thread got way off track ;) P4man, the same kind of thing could blow the pins in a 4pin molex connector for the same reason, have you measured the voltage on your 12V rails to see if you've got bad sag? Hmmm. same kind of what thing? Also not sure what a "bad sag" is, but now that you mention it, the burnt molex connector was on my mining rig and that was with an old rather crappy 450W PSU that only powers a single 5850 and a hdd. I have measured voltages (just with a multimeter) and they seem stable, but 12V is only ~11.6-11.7v under load. If you meant to ask if there could be a relationship with my desktop where the 4 pin fell out; no, none. Different machine, and this one has a nearly new Zalman 650W thats working perfectly. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: cicada on November 16, 2011, 08:10:43 PM Also not sure what a "bad sag" is, but now that you mention it, the burnt molex connector was on my mining rig and that was with an old rather crappy 450W PSU that only powers a single 5850 and a hdd. I have measured voltages (just with a multimeter) and they seem stable, but 12V is only ~11.6-11.7v under load. An example of 'bad sag' - I had a 450W diablotek (avoid!) PSU who's 12V rail sagged to 10.4V powering just a 35W celeron and a single 5830. I turned it off immediately and thanked the gods it hadn't fried anything up yet. Anything >11.5V I'd consider perfectly acceptable on a 12V rail, so yours isn't bad. I was getting 11.8V or so on a nice Corsair 750W running 3 cards. If you meant to ask if there could be a relationship with my desktop where the 4 pin fell out; no, none. Different machine, and this one has a nearly new Zalman 650W thats working perfectly. Nah the 'same kind of thing' i was referring to was the voltage sag. Basically, like a chain, the weakest point in a circuit is going to burn out when over-current. In m3sh3aD's unfortunate case it was his ATX header, was thinking in yours it was the molex plug. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: m3sSh3aD on November 17, 2011, 09:31:55 AM It as burnt ALL of the shroud around end pin of the 20 pin connector. through one side of the connector on the MoBo nearly and a pin on the 4 pin connector on the PSU. It is a AK1200, not HCP1200 i picked up for 145 from 210 or something. Basically HACP replaces the AK.
It's dangerous, wish i could get it independently tested but that could be time consuming, costly and may not give me an answer in the end. I replaced the mobo with a MSI one and not a problem. Although thatAK will not be plugged in another mobo with that damage again Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 17, 2012, 07:39:00 AM Just to confirm my OP. Yesterday another 5850 arrived, and while I was waiting for a new PSU, I tested it with what I had, using one 2 molex -> PCIe cable and one 1 molex > PCIe cable.
Card ran fine for a few hours, then I started overclocking. After 2 hours or so at 850 MHz, something started to smell burned. Sure enough, the single molex to PCIe cable was hot to the touch and where the 2 yellow cables connect inside the molex connector a brown stain was forming. It was melting. The 2 molex to PCie cable, which uses only 1 yellow wire per connector, was fine. Morale: use these things at your own risk. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 10:57:41 AM What a god-awful hack crimping two 20 AWG wires together at the molex(1) contact, where all the current will flow...
That sure is a fire waiting to happen. And no matter what, don't ever use a sata-> molex adapter for powering anything more than a hard drive! The SATA connector is rated much lower than that molex connector, at 4.5 amps max under ideal circumstances. https://i.imgur.com/ry1z1.jpg Notes: (1) Actually, the four contact "Molex" connector should be called the 4 pin peripheral connector but everyone just calls it a molex. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 17, 2012, 11:03:28 AM Would it be safe to solder these things yourself?
I have an old spare PSU thats rated for 450W (350W on 12V, one 14A and one 15A rail) which should be plenty to power 1 5850 until my new PSU arrives. Thing is, its old and has zero PCI-E connectors and only 2 molex connectors. And like a dozen SATA connectors. If I were to cut my now defunct molex to PCIe adapter (keep the PCIe part), and cut some wires from the PSU (sata or maybe even from the motherboard or 4/8 pin CPU connector?) and manually solder them.. would that be a good idea or drop dead stupid? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 11:23:46 AM If you feel comfortable with a soldering iron in your hand, rock on.
Twist the copper wires together and don't skimp on the solder, give them as much as they will soak. Just don't forget to put the shrink-wrap insulation in place before soldering the wires together :D PCIE 6-pin/8-pin plugs and contacts can be easily ordered online, you can make any kind of connector you need without that messy wire soldering. Also, that 2*molex -> PCIE 6-pin you mentioned before looks up to the job. EDIT:: Since you mention this is an old PSU, have you tested whether it will run with no load at 5V / 3.3V rails? More importantly, won't it jump out of spec under the cross-load condition? You might need to load the 5V rail with a power resistor. Do you happen to have a multimeter lying around? Power up the card, and measure voltage on some other 12V cable connected to the same rail. A double-rail design will likely have rail1 connected to the ATX12V connector (and perhaps the ATX 24-pin connector) and rail2 to all sata/peripheral connectors. When in doubt and the user manual is inaccessible, open up the PSU and verify rail setup visually. Measure again with the card having ran fully overclocked for a couple of hours. Better safe than sorry. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 17, 2012, 12:39:34 PM If you feel comfortable with a soldering iron in your hand, rock on. Twist the copper wires together and don't skimp on the solder, give them as much as they will soak. Just don't forget to put the shrink-wrap insulation in place before soldering the wires together :D PCIE 6-pin/8-pin plugs and contacts can be easily ordered online, you can make any kind of connector you need without that messy wire soldering. I already purchased a new PSU to be able to handle at least 3 cards. Since it wont arrive today, I just want to get through the weekend Quote Also, that 2*molex -> PCIE 6-pin you mentioned before looks up to the job. Yeah, but I can only use 1 of those with this PSU, since it only has 2 molex connectors. I need somthing to power the second PCIe connector. I could use a second PCIe connector from another PSU, which is not up to the job of powering the entire card (on top the 5870s it has to deal with), but it might be enough for "half a 5850". Intuition tells me its a terrible idea to power a GPU from 2 different PSUs, but Artforz claims it should be no problem... so now I have to decide whether to believe him (and potentially risk a card), or cut some wires (and potentially risk an obsolete PSU). Quote EDIT:: Since you mention this is an old PSU, have you tested whether it will run with no load at 5V / 3.3V rails? More importantly, won't it jump out of spec under the cross-load condition? You might need to load the 5V rail with a power resistor. Ill hook up a DVD drive or something, I suppose that should do? Quote Do you happen to have a multimeter lying around? Power up the card, and measure voltage on some other 12V cable connected to the same rail. I remember checking it a while back with another GPU, and it was okay-ish. 11.3V or so under load. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 01:06:47 PM 11.3V is already out of spec by 0.1V :-\
IDK how exactly you tested that PSU but do keep an eye on the voltage... it can be a sign that the unit is having a really tough time. Let's cross the fingers and hope that the PSU can last a couple of days. Not a DVD drive - the power utilization is nil when not actively reading a disc. As it turns out, Art was correct - PCIE graphics manufacturers are prohibited from creating a galvanic link between PCIE power sockets. Plug1 powers a set of voltage regulators and Plug2 - another set. The VRM controller regulates those subsets independently and in general makes sure they behave. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: bulanula on February 17, 2012, 01:20:48 PM Quote from: jake262144 As it turns out, Art was correct - PCIE graphics manufacturers are prohibited from creating a galvanic link between PCIE power sockets. Plug1 powers a set of voltage regulators and Plug2 - another set. The VRM controller regulates those subsets independently and in general makes sure they behave. So what exactly does this mean in practical terms ? Can mix and match PSUs on an individual GPU without problems ? Thanks ! Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 17, 2012, 01:38:59 PM If you feel comfortable with a soldering iron in your hand, rock on. Twist the copper wires together and don't skimp on the solder, give them as much as they will soak. Just don't forget to put the shrink-wrap insulation in place before soldering the wires together :D PCIE 6-pin/8-pin plugs and contacts can be easily ordered online, you can make any kind of connector you need without that messy wire soldering. I already purchased a new PSU to be able to handle at least 3 cards. Since it wont arrive today, I just want to get through the weekend Should be fine. For short term you likely don't even need soldering just wire nuts. Take that Molex -> PCIe adapter. Cut the molex end off. Take the PSU find some 12V and ground wires to match, cut the ends off. Match and wire nut them. Jumper PSU and check all voltage to ground readings w/ multimeter. If you want to get fancy the "pins" in PCIe/Molex connector are available in most home improvement stores or radio shack. Just rip one out of a bad connector and bring it in to match it up. A pair of needle nose pliers will crimp them in a pinch and a drop of solder will make sure it isn't going anywhere. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 17, 2012, 01:51:52 PM (1) Actually, the four contact "Molex" connector should be called the 4 pin peripheral connector but everyone just calls it a molex. Yeah it bugs me too but if you don't say Molex nobody has any idea what you are talking about. Molex makes a lot of connectors for example this one (Molex part #45559-002 and #45558-002) http://www.molex.com/mx_upload/family/graphics_power/MiniFit_PCIExp_300.jpg :) and most "Molex" connectors aren't made by Molex anyways (they are generics to save 0.25 pennies per connector). Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 17, 2012, 01:59:56 PM Should be fine. For short term you likely don't even need soldering just wire nuts. ??? How would that be any better than the adapter I almost set on fire? I dont even see how my soldering would be better. FWIW, here is a picture of the adapter after the facts: http://img811.imageshack.us/img811/6937/sdc10732d.jpg http://img821.imageshack.us/img821/9430/sdc10731i.jpg (right click / view image for full res) Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 17, 2012, 02:11:41 PM If I remember right that was due to reduced # of pins being used thus increasing the current on each pin and/or bad quality crimp at the connector. Right?
I am just saying to use the connector from a Molex -> PCIe6 adapter simply as a source for the connector itself, unless you happen to have some PCIe 6 pin blank plugs laying around. Wirenuts can handle high amperage just fine. Most of the wiring in your wall has wirenuts and they can pull 15A per connector. On a 6 pin connector w/ all 3 12V wires connected at most each conductor is handling ~2A. That is nothing for the wire itself or any quality wire nut. Just make sure the connectors are sold (no loose crimps or bad solder joints). If you have a spare Molex to Molex adapter (sometimes used as Y connector for fans) or Molex to PCIE you can destroy it for more wiring which already has pins crimped. If not you could always buy some pins and crimp them yourself. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 17, 2012, 02:40:13 PM If I remember right that was due to reduced # of pins being used thus increasing the current on each pin and/or bad quality crimp at the connector. Right? The connector pin itself looks fine actually, its where the 2 cables are crimped (cramp, crump?) together that its molten. Thats why I wonder doing that myself would be any better. Ill just go the *cough* new safe way of using 2 PSUs for 1 card and see what happens. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 17, 2012, 03:02:04 PM If I remember right that was due to reduced # of pins being used thus increasing the current on each pin and/or bad quality crimp at the connector. Right? The connector pin itself looks fine actually, its where the 2 cables are crimped (cramp, crump?) together that its molten. Thats why I wonder doing that myself would be any better. Ill just go the *cough* new safe way of using 2 PSUs for 1 card and see what happens. Well 2 PSU is always an option. Lets us know. I was saying assumming you had enough 12V wires only use 1 wire per connector. i.e. 12V from PSU ----- wire nut ------ pin in PCIe6 connector 12V from PSU ----- wire nut ------ pin in PCIe6 connector 12V from PSU ----- wire nut ------ pin in PCIe6 connector Ground from PSU -- wire nut ------ pin in PCIe6 connector Ground from PSU -- wire nut ------ pin in PCIe6 connector Ground from PSU -- wire nut ------ pin in PCIe6 connector If you didn't have enough individual conductors I would make all the connections in the wingnut to keep load on each pin down. wire nut ------ pin in PCIe6 connector 12V from PSU ----- wire nut ------ pin in PCIe6 connector wire nut ------ pin in PCIe6 connector wire nut ------ pin in PCIe6 connector Ground from PSU -- wire nut ------ pin in PCIe6 connector wire nut ------ pin in PCIe6 connector Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 03:03:16 PM I have been running overvolted sapphire extreme HD5850s with this kind of molex adapters for months without problems. Don't take my word for it, do your own math: the spec clearly says 1.5A per contact. Three contacts equal 4.5A per connector (http://www.molex.com/webdocs/datasheets/pdf/en-us/0675810000_CRIMP_TERMINALS.pdf).Moreover, the sata power connector was by a no means engineered for reliability. Instead, a lot of emphasis was put on ease of connection/disconnection. You did notice this is a SATA - "molex" adapter, not a molex - PCIE adapter, right? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 03:13:00 PM ... wire nut ------ pin in PCIe6 connector 12V from PSU ----- wire nut ------ pin in PCIe6 connector wire nut ------ pin in PCIe6 connector wire nut ------ pin in PCIe6 connector Ground from PSU -- wire nut ------ pin in PCIe6 connector wire nut ------ pin in PCIe6 connector Did you mean: /------ pin in PCIe6 connector 12V from PSU ----- wire nut------- pin in PCIe6 connector \------ pin in PCIe6 connector /------ pin in PCIe6 connector Ground from PSU -- wire nut------- pin in PCIe6 connector \------ pin in PCIe6 connector (three PCIe 6-pin cables packed together at one wire nut) Anyway, I don't see the advantage of choosing a wire nut over soldering... the latter pretty much eliminates the point of failure. Both are 5 minute jobs... Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 03:19:10 PM The connector pin itself looks fine actually, its where the 2 cables are crimped (cramp, crump?) together that its molten... The problem lies at the contact-wire interface.Look at the difference wire gauge makes (http://www.molex.com/pdm_docs/ps/PS-8981-4M4P.pdf): 10 amps with 16 AWG wiring drops to merely 6 amps with 22 AWG. A dab of solder might be to the connector what thermal paste is for CPUs. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 17, 2012, 03:20:22 PM Did you mean: (three PCIe 6-pin cables packed together at one wire nut) Yes. Thanks for the improved ASCII diagram. No problem using 4 conductors. Just be sure to use proper sized wirenut based on gauge and # of conductors. Quote Anyway, I don't see the advantage of choosing a wire nut over soldering... the latter pretty much eliminates the point of failure. Both are 5 minute jobs... He said he only needs something for the weekend and I wouldn't call a wirenut a 5 minute job. :) Nothing wrong with soldering either but if it is a crap PSU and he is just looking for something to run the weekend I personally wouldn't waste the time soldering. Maybe I am just lazy. :) Now if it was some custom build (like using 3KW server PSU to power 10 GPUs) I would take the time to solder and inspect each joint. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: malevolent on February 17, 2012, 03:21:31 PM I have been running overvolted sapphire extreme HD5850s with this kind of molex adapters for months without problems. Don't take my word for it,do your own math: the spec clearly says 1.5A per contact. 3 contacts equal 4.5A (http://www.molex.com/webdocs/datasheets/pdf/en-us/0675810000_CRIMP_TERMINALS.pdf)You did notice this is a SATA - "molex" adapter, not a molex - PCIE adapter, right? Sorry I think I need some sleep, I meant molex-pcie adapters, but SINGLE molex, as this is what sapphire supplied their 5850 extreme cards with. Not sure but I think the reason why P4man had his connectors burned was either: a) he was unlucky to stumble upon a faulty adapter with congenital faults or b) there are numeours companies producing these adapters and some are of worse quality than others. so far I only dared to connect a X600XT with sata adapter ;) Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 03:27:16 PM Sorry I think I need some sleep, I meant molex-pcie adapters... No problem, I'm glad we cleared this misunderstanding.Actually, thanks for giving me a reason to link the manufacturer's spec sheet for everyone to see. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 17, 2012, 03:39:28 PM Sorry I think I need some sleep, I meant molex-pcie adapters, but SINGLE molex, as this is what sapphire supplied their 5850 extreme cards with. Not sure but I think the reason why P4man had his connectors burned was either: a) he was unlucky to stumble upon a faulty adapter with congenital faults or b) there are numeours companies producing these adapters and some are of worse quality than others. so far I only dared to connect a X600XT with sata adapter ;) Now that you mention it, these connectors most likely came bundled with a sapphire 5850. Its not likely I would have stumbled upon TWO faulty connectors, in the first post I describe one that burned, and now, x months later I tried with another one and burned it again. Keep using them at your own peril. At the very least check them. Anyway, card is working fine atm powered by 2 PSUs (and 2 times 2xmolex->PCIe). Im not loading the 5v yet, but voltage seems decent (11.6v) and if the PSU blows up, so be it. I dont have a spare sata drive and all the other stuff I can think off needs 4pin molex. Maybe Ill cut a sata connector and solder a fan or bycicle light bulb to it, Ill see what I can find. Thanks for all the help. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 17, 2012, 03:47:49 PM Anyway, card is working fine atm powered by 2 PSUs (and 2 times 2xmolex->PCIe). Not broken (yet :P), don't fix. If the PSU works fine with no 5V load it's all for the better.Im not loading the 5v yet, but voltage seems decent (11.6v)... Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: BTC guy on February 18, 2012, 01:11:01 AM I never trusted those adapters. I would rather spend the money for a psu that has enough PCIE cables.
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: TheHarbinger on February 18, 2012, 01:24:32 AM I never trusted those adapters. I would rather spend the money for a psu that has enough PCIE cables. Well, point me to a 1500W Seasonic with 12 PCIe power cables. :-* Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: malevolent on February 18, 2012, 09:08:32 AM Keep using them at your own peril. At the very least check them. Yes I did, several times, first time when you created this topic. They did not melt/burn so far and aren't hot. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 18, 2012, 09:23:24 AM Keep using them at your own peril. At the very least check them. Yes I did, several times, first time when you created this topic. They did not melt/burn so far and aren't hot. You are using them on a 5850 right? What clock are you running them at? im running one at 900 the other at 850. On a sidenote, as I was switching cards on a different rig the other day, I removed a 6pin PCIe plug (no adapter) from one of my older PSUs. It has a white PCIe connector and it had a brown tint near one of the pins as well. Nothing too serious, but clearly it had gotten hot. This PSU was powering a 5870 @ 1 GHz. So i began wondering if perhaps underpowered PSUs dropped voltage too much, increasing the amperage, but it measured 11.7V under load. So Im not sure whats causing it with me ??? I do know I dont like it one bit. And that I wish all connectors where white so you can actually see if something is getting too hot or has ever gotten too hot. There is no way to tell with these black connectors until its likely too late. My new PSU cant arrive soon enough... though Im not sure this really is a PSU problem. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: malevolent on February 18, 2012, 09:45:24 AM You are using them on a 5850 right? What clock are you running them at? im running one at 900 the other at 850. On a sidenote, as I was switching cards on a different rig the other day, I removed a 6pin PCIe plug (no adapter) from one of my older PSUs. It has a white PCIe connector and it had a brown tint near one of the pins as well. Nothing too serious, but clearly it had gotten hot. This PSU was powering a 5870 @ 1 GHz. So i began wondering if perhaps underpowered PSUs dropped voltage too much, increasing the amperage, but it measured 11.7V under load. So Im not sure whats causing it with me ??? I do know I dont like it one bit. And that I wish all connectors where white so you can actually see if something is getting too hot or has ever gotten too hot. There is no way to tell with these black connectors until its likely too late. My new PSU cant arrive soon enough... though Im not sure this really is a PSU problem. 5850 are at 970 and 1.17V what psu was it? if the PCIe plug gets hot then there's clearly something wrong, even the best psus can break Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 18, 2012, 10:36:10 AM 5850 are at 970 and 1.17V what psu was it? if the PCIe plug gets hot then there's clearly something wrong, even the best psus can break Oh its definitely not the best PSU; its an old coolermaster 450W that I salvaged. But it only has to power that 5870 (and a hdd to load the 5v). Even so, rubbish PSU or not, why would the connector overheat ??? Voltage appears stable and the 5870 isnt complaining afaict; at least it runs stable, cool and is my best overclocker (does nearly 1.1 GHz at stock voltage). .I could imagine the PSU blowing itself up, but I see no reason for the connector to heat up. OH well, I changed it so now it only has to power half that 5870 using a double molex adapter and Ill retire it next week. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 18, 2012, 02:04:23 PM May have found the cause.
The left most 2 wires are from one of those burnt molex>pci-e adapters (and no, I didnt mess up stripping). The right 4 wires are from my PSU's 12V 4+4 pin. http://img839.imageshack.us/img839/1007/sdc10734y.jpg I dont know how to measure the thickness or calculate how many amps those wires can carry, but that looks way too flimsy to me. Outside diameter is the same though, so no way to tell unless you cut them. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 18, 2012, 02:50:49 PM Read the tiny print on the cables. Look for the AWG rating, like 20 AWG. The higher the number, the lower the wire diameter.
AWG 18 is a recommended minimum, 16 is golden, 20+ is just inadequate for power-hungry cards as wire gauge makes one hell of a difference for the That adapter of yours is outrageously full of fail, even as far as crappy and inexpensive adapters are concerned. If you have another of those surefire (or was it sure-to-catch-fireTM??) molex->pcie adapters and a soldering iron, try using a dab of solder as an electrical interface between the wires and the contact surface. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 18, 2012, 03:19:24 PM Indeed, but it does say AWG 18, so you are saying that ought to do?
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 18, 2012, 03:26:09 PM If your PSU cables also say 18 AWG someone was clearly dishonest ::)
The difference is undeniable. Not only outrageously crappy but also mislabeled - why doesn't this come as a surprise? This is precisely what many low-end OEM manufacturers do... If you solder those wires or just go lazy and use wire nuts you should be ok. Should you go with wire nuts make sure to twist those flimsy wires firmly together. Thanks for uploading high quality pictures to document the issue. This topic should be made a sticky. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 18, 2012, 03:33:38 PM Voltage appears stable and the 5870 isnt complaining afaict; at least it runs stable, cool and is my best overclocker (does nearly 1.1 GHz at stock voltage). .I could imagine the PSU blowing itself up, but I see no reason for the connector to heat up. A couple of possibilities. a) the connector wasn't solidly connected increasing resistance and thus increasing current. b) the PSU is sagging under high load. Did you test 12V on the same rail while card was under full load? c) the connector is bad. Given your rash of other bad connectors I am leaning towards B. The VRM will handle voltage out of spec so the power to the GPU will be unaffected. Of course the harder regulation will make them (VRM) run hotter. Although any connector could be bad the fact that you have had numerous bad ones compared to say me with zero on 19 5970s = 38 connectors total makes me think that PSU is sagging badly under load. Also it may not sag all the time, maybe it only sags 30-40 hours of sustained higher current when the PSU is operating at a higher temp. IMHO Voltage issues are hard to pin down which is why I keep it simple. I generally use Seasonic PSU (or Seasonic rebrands) with giant high current single 12V rail. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: jake262144 on February 18, 2012, 03:42:23 PM A couple of possibilities. a) the connector wasn't solidly connected increasing resistance and thus increasing current. b) the PSU is sagging under high load. Did you test 12V on the same rail while card was under full load? c) the connector is bad. Given your rash of other bad connectors I am leaning towards B. I strongly disagree. Power fluctuations high enough influence a connector would either hang or kill the card outright. There have been no stability issues. I'm of the opinion that the cheap generic connector just made poor contact leading to a temperature rise. Mind you that the "rash of bad connectors" happened elsewhere, not at the PCIe plug. The molex-pcie adapters are clearly substandard, look at the pics. The PSU is likely ok. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: P4man on February 18, 2012, 05:01:38 PM If your PSU cables also say 18 AWG someone was clearly dishonest ::) The difference is undeniable. Actually, I never said what was on the PSU cables, and I assumed it to be different since I assumed the labeling on the wires to be correct. But WTH, you are right, it says AWG 18 on the PSU cables as well, and they are at least 4x as thick! THis is getting interesting. I can easily see someone cutting corners by using subpar wires, but who else than a producer of wires would actually forge those tiny numbers on the wire that no one ever reads? So it appears some shady supplier of wires ripped off whoever made those adapters, saving a few pennies worth of copper. Doh! BTW, I also checked my 2xmolex > PCIe adapters that work fine and it says AWG 20, which is supposedly thinner thatn AWG18. I havent cut them, but I assume they will indeed be thinner than the PSU cables (which are rather massive), but probably at least 2x thicker than the shoddy adapter even if the labeling suggests the opposite. Im also thinking that whoever made the single molex adapter deliberately bought thicker wires to get away with 1 molex plug, but due to a scam he ended up getting wires that are woefully inadequate. Quote If you solder those wires or just go lazy and use wire nuts you should be ok. I had just finished soldering when the door bell rang and a brand new 850W was delivered. Hadnt expected delivery on saturday :). But knowing now that those supposed AWG18 cables really are far thinner than they should be, Ill just cut the connector again and throw it away. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: DeathAndTaxes on February 18, 2012, 05:18:31 PM Quote from: P4man link=topic=51740.msg756265#msg756265 Actually, I never said what was on the PSU cables, and I assumed it to be different since I assumed the labeling on the wires to be correct. But WTH, you are right, it says AWG 18 on the PSU cables as well, and they are at least 4x as thick! THis is getting interesting. I can easily see someone cutting corners by using subpar wires, but who else than a producer of wires would actually forge those tiny numbers on the wire that no one ever reads? So it appears some shady supplier of wires ripped off whoever made those adapters, saving a few pennies worth of copper. 2 pennies * 1 million units = some moey. Hopefully your new unit is solidly built, you can use direct PCIe connections with thick wiring and leave all this power problems behind. Morale of the story. Use high quality power supplies with right number of connectors to save yourself a lot of headaches. :) Anyways you got me looking My Enermax 1350 uses 16 gauge wires which is likely overkill (although I haven't cut them to make sure ??? ). I would hope Enermax (and any other first tier brand) values their brand enough to QA their products and avoid cutting corners but I guess you never know. Quote Im also thinking that whoever made the single molex adapter deliberately bought thicker wires to get away with 1 molex plug, but due to a scam he ended up getting wires that are woefully inadequate. Or was in on it. :) Many companies in China and elsewhere will gladly build anything you want to "spec" and if "spec" using 24 gauge, a thicker jacket and stamped 18 gauge to hide it will they will build it that way if you are paying. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: mrkubanftw on May 02, 2013, 12:54:18 AM Cable isn't a problem. According to the electrical engineering site here: http://www.rbeelectronics.com/wtable.htm - for cable runs of less than 3 feet (OK for GPU connections, surely), with 12V supply, 18 AWG is the recommended gauge for up to 40A or 240W. If you're using 16 AWG, that's the recommendation for 50A / 300W. So according to this, the *cable* itself is good enough to supply an entire 5850 with ONE yellow wire and ONE black wire... and these are the 'recommended' gauges so I doubt the cable would ever get hot. I've tried some rather dodgy practices in the past and never come across hot cables, except where a GPU was blowing its hot exhaust air onto the cable. Pure resistive heating? Not really ever seen a problem (other than my 10A rated 240V extension lead powering the Shelf Rig at 2.5 kW and getting VERY hot). The problem seems to be with the connectors. As plastic says, the single Molex -> 6-pin connectors are very common and still supplied with many new cards. Even quality stuff like my Asus DirectCU II 6950s. I suppose it depends completely on the thickness of the pins inside the Molex connector. As P4man demonstrated, the cables weren't at fault, but the crimping point between the cable and the Molex connector. If all Molex pins are the same, then there could be a problem... but if the GPU-supplied Molex plugs have thicker, uprated crimped connectors then things should be OK. Personally I **much** prefer to use 6-pin Y-splitters, and power any twin-6-pin GPU using one 6-pin output from the PSU. The connectors themselves are rated higher than the Molex and, as pointed out above, the wire itself is NOT a problem. So every single card I use is powered from one 6-pin PSU cable, with a Y-splitter attached. Not had any problems yet. However I will definitely test for hot connectors - since the cables shouldn't have a problem with 200-odd W, they won't get hot, but the plastic connectors most certainly can if not rated for 20-40A. You are correct. That gauge wire would support 40 amps minimum all day on one lead. Not to mention my cooler Master power supply that has 2- 6pin pcie connectors are ran off the same 3 wires and spliced to two connectors. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: AniceInovation on May 03, 2013, 02:31:55 AM I bought once 20 of those molex-to-pciex power connector on ebay, used 2 and they lasted one week. And they were double molex conectors.
I use some quality single molex conectors for the last 20 months and no problems. Moral of the story: Don't save on these, and you'll have no problems. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: ryantc on May 03, 2013, 06:13:31 PM I was using a double 4-pin to one 6-pin connector on my 7850, that one actually came with a old 3850 video card.... :D, and it's 18AWG, doing well.
Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: pekv2 on May 03, 2013, 09:15:54 PM Thanks for the headsup on keeping an eye on which convertor connectors to use. That's crazy.
Sticky! Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: rograz on May 04, 2013, 10:22:05 PM Or was in on it. :) Many companies in China and elsewhere will gladly build anything you want to "spec" and if "spec" using 24 gauge, a thicker jacket and stamped 18 gauge to hide it will they will build it that way if you are paying. Let's not forget copper is so expensive, let's save a few more cents and go with aluminium. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: PeZ on May 04, 2013, 10:41:53 PM If you plan on using a 4 pin to 6 pin connector, you should use the one supplied with your video card.
Nvidia and AMD 4-to-6 pin connectors are wired differently. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: BBQKorv on May 05, 2013, 01:21:27 AM If you plan on using a 4 pin to 6 pin connector, you should use the one supplied with your video card. Nvidia and AMD 4-to-6 pin connectors are wired differently. Could you link that "fact"? Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: ssateneth on May 05, 2013, 04:53:43 AM If you plan on using a 4 pin to 6 pin connector, you should use the one supplied with your video card. Nvidia and AMD 4-to-6 pin connectors are wired differently. lold. this guy has no idea what he is talking about. Title: Re: 4 pin molex to 6 pin pci-e connector. Word of warning Post by: Eb0la on May 31, 2013, 03:19:13 AM If you plan on using a 4 pin to 6 pin connector, you should use the one supplied with your video card. Nvidia and AMD 4-to-6 pin connectors are wired differently. http://files.myopera.com/drlaunch/albums/94593/thumbs/orry001.jpg_thumb.jpg http://gallery.quattroworld.com/d/5108-1/O+Rly.jpg http://www.perryvsworld.com/media/2/20130514-o%20rly.jpg http://a1.ec-images.myspacecdn.com/images02/115/51c7866917254c72ad7ce34f4afb5e40/l.jpg http://thewritersadvice.files.wordpress.com/2012/06/idiot2.jpg |
