Bitcoin Forum

Hi there, just a quick question: Can I use a splitter to get 10 PCI connectors instead of 8?

Thanks in advance!

If you're looking to run an S7 and you have 16AWG cable, 7 should be plenty. At under 400WDC per board (more like 380) you'd be under 200W per cable using two jacks per board, which a good 16AWG cable should handle pushing 300W without a lot of trouble. You'd want to keep an eye on 'em but it should be fine. 18AWG cable, no you better try and use all 3 jacks.

A good answer to your question does depend on what you intend on doing with your 10 jacks.

Yup, attempting on running one of those, as far as im concerned Im using 12 AWG cables at home, but that could change. The S7 does need 10 PCIe jacks..

Bitmain is being conservative, and it's good that they are - consider the difference between an S3 (350W, 4 jacks) and a KNC Neptune (400W, 1 jack). Which has a better track record for not bursting into flames?

400W can be run off two cables if you have good cables. I wouldn't trust 18AWG for more than about 150W where I'd trust 16AWG for 250 without batting an eye. My opinion, it's safe with two cables if you have good cables. If it makes you feel any better, I ran about 30 AM Tubes (200W per module) off a single 16AWG cable per module for six months without a single issue.

Hehe Im quite confused. When you speak of good cables do you mean the quality of my PSU PCI cables? Or are you referring to the internal wiring of my house?

The question is about your PSU cables. The answer, then, is also about your PSU cables. If your PSU has PCIe cables made from 16AWG wire, it should be okay. If your PSU has PCIe cables made from 18AWG wire, I'd say it's a poorly-thought-out design.

How can I know the quality of the cables? This is the product http://holybitcoin.com/product/holy-bundle/

Thanks for your time, Its getting clearer to me

My bad! So 7 cables should do the trick! Thats awesome

I am pretty certain they are going to send same kinda paperwork S5+ came with.  Even if 2 would do it if they catch you doing it voids warranty.

So if they catch someone using 2 and in warranty I think they will void it from their paper at least if they keep it same as S5+.   They considered it something thing like improper powering or something like that.

I wonder if they'd complain if he used a splitter from one of his nice sturdy 16AWG cables to a pair of jacks. It'd be pretty much just as safe.

Good question I would get a official anwser on it.  I'm not sure they were very very vague on what improper powering could be.  It for sure is using only 2 from their eyes.  They emailed me a paper and sent one with S5+ to make sure I did not even think about 2 only.

But not sure if you have them on a proper splitter as they don't say you cannot do it.... so more possible on that way for sure.

two out of six evga 1300 cables are already split. i see no difference in splitting the other four as long as a single red cable can handle 266w (it will be 133w per connector, though). I don't have 220/240V in my house (apart from the dryer and stove), so ordering their PSU is out of the question.

So, can a single 16AWG cable handle 2 connectors safely? (Assuming I splitted the PCI cable)

As long as you have two entire cables per board - one split, one unsplit - should be fine. It's up to Bitmain whether that's "fine" by their standards. Running 3 cables would be better, and with as many idiots as there are in the world thinking their junker 20AWG Wal-mart supplies can do anything right, I can understand why they'd insist on three cables.

The cables you have will do the job safely, even with a splitter on one cable per board.

Great, I also found out on the internet that a a 16AWG cable can handle up to 3.7 Amps
Source: http://www.answers.com/Q/How_much_current_can_a_16_gauge_wire_handle

Depending on your options I would look into 240.  It really is nice to have using a PDU and being able to get a lot of juice is very nice. I do see that it's not the option for everyone.  

What I think is one of the server kit people are going to have a higher then normal sales rate with S7 release.  I see them putting out a kit with enough PCIe cables on it.   They have a few weeks from release date of S7 to get these kits in stock and sell them. And I predict they will do just that.

I've been turning away DPS2K sales all week on account of we're out of stock. I had a choice to put money down on a new batch of boards or buy some new machinery, and since it took most of a year to sell the last batch of boards it didn't seem a good investment.

A pair of my 750W Dells load-balanced should run an S7 quite nicely. A single 1300W server supply should also do pretty well. You're right; a lot of supply kits are gonna get sold in the next month.

Dang I was honestly hoping some of those would go your way.  I love that you have a good ethic twords how you treat people, and think highly so far of your products after testing the usb drive.

I can understand the decision.  I think few were expecting them to keep S5+ design.  I would have bet for sure it was going to keep 2 blade design.   I do give bitmain credit on finding a way to make more choose their psu though.   They are the other one to pick up sales from having 10 PCIe on S7.

I do fear how you mention junk wal-mart pci-e splitter.  I fear some will try to save a few bucks and cheap cords will get hot and melt.  I see that being a real issue if someone tries to go out to a store and get some of the off the shelf splitters.

Keep in mind that power supply is 1300w at 240v and only 910 at 120v.

Thats true, thanks for the heads up

 Dunno where they got that answer from, but it's WAY on the low side.

 16 AWG in most usage is good for at least 8 and possibly as high as 10 amps.

 The national electric code doesn't go that low, but if you take their rating for 14 AWG (a VERY VERY conservitive 15 amps) and pro-rata for the relative circular mil area of a 14AWG to a 16AWG you get a much more accurate while still conservative figure.



 BAD timing.
 8-O

I think they were talking about 16 awg for a splitter.  For a 2 PCIe splitter to be exact.  So it's not going to get anywhere near 10 amps.

But I think your thinking of the electric cord running, and they are saying for a splitter.  So 2 different things.

Here's a better figure of ampacity for stranded cabling in DC setting: http://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity

More importantly however, the connectors used for PCIe (Molex mini-fit JR: http://www.molex.com/pdm_docs/ps/PS-5556-001.pdf) specify a maximum amperage of 8-9A per 16awg circuit in a 3-powered-circuit connector, depending on the type of pins used. Or, 288-324W maximum per connector.

They are also rated to a maximum of 105*C (including a maximum 30*C temperature rise over ambient for the connector).

Edit: To answer your question, Bitmain "requires" that all 3 PCIe sockets are used per hashing board.  Each hashing board on an S7 draws somewhere around 360-370W DC, so with proper 16awg cabling (Scott's is good quality 16awg), if you were to use a splitter for 2x of the PCIe sockets to feel better about it (and be 100% sure not to violate warranty terms), you would be well within the safe range for amperage of the wiring and connectors/pins.

It's quite possible that this ongoing consternation of how many PCIe power connectors are needed relates to your interpretation of the PCIe specification for the power connector. I think the original spec only REQUIRED that two of the +12V lines be present. All three of the GND wires were required, but it was perfectly "legal" to only have two +12V lines. So if you interpret the PCIe spec very conservatively, 3 connectors would guarantee that there were 6 actual +12V pins.

Of course virtually no PSU vendor did that so, all three +12V pins carry current these days. So with two PCIe connectors on a current PSU, you get 6 conductors, which is the same as three "legal" PCIe connectors.

Since they don't want you to have more than one +12V rail for a blade, I think that's a pretty clear indication they are all joined in parallel on the board. In addition, things still work well, even if one of the pins has a marginal crimp, or just fits poorly, if all the connectors are used.