850Watt PSU Blown with a 7950 + 280X

[carlb007]

Hi all.
Just looking for some advice here as im not sure whats happened. I have/had a  850watt powercool psu (see here: http://www.scan.co.uk/products/850w-psu-powercool-pcpc850auba-80-eff-80-plus-sli-crossfire-eps-12v-quiet-fan-atx-v22)
I just setup a new rig with 1x R280X and 1x 7950 graphics card in (from a powered riser card). The PSU only has 2 8pin PCIE power connectors edspite being titled as SLI, so i plugged in as follows:
1x8pin into the 280x
1x6pin into the 7950
2xmolex to 8pin pcie for the 2nd power slot on the R280X off 1 cable coming from the psu
2xmolex to 6pin pcie for the 2nd power slot on the 7950 + 1 molex to the pcie riser card off the 2nd cable coming from the psu.

the 2 12v Rails were rated at 16A which should be 190W.

I plugged in, powered up, started mining just fine. Both cards running. I then changed the power-tune in config file from -20 to -10 via RDC, and suddenly heard a 'POP' in the other room. Went to inspect and the entire machine was off. Unplugged everything and turns out the fuse had blown in the power cable.
Swapped power cable over and just turned the psu on (not plugged into mobo) and 'POP'. Blew the 2nd fuse in the new cable.

Basically the PSU is dead - but what i wanted to know was - have i caused this or was i just unlucky with a faulty unit? What should normally happen if you over load a psu would it smoke up - id expect them to have some sort of resettable fuse in them.
The 2 cards should only be a max of 500watts (less because powertune was still -10%) but im not sure if its because i then utilised the riser on the same channel or what? - didnt actually need the riser in this case i was just testing it but a bit nervous about trying a riser on any of my other boards now - i bought 5 with the hope of adding a 3rd card to my other boards. What power supplies does everybody use or recommend for 3x280x or 3x7950s? Do any exist with 6 pcie power cables or does everyone utilise the molex adapters like i have?

thanks in advance!

[pletharoe]

There are plenty of PSUs with ample PCI-e connectors, you've just got to be careful reading the specs before you buy.

850 watts would be the minimum PSU I'd be happy using for the two cards.  You may have been running powertune, but I'm not sure how much difference it makes when the GPU is running flat out anyway.

Even if you do think that the machine will use (say) 500 watts.  That is only an average figure.  What if there's a spike in power requirements, or the power supply to your home isn't 100% clean?  Both examples could put much higher transient loads onto the PSU.

[pungopete468]

How old was your PSU?

They decline in output capability over time...

[Prelude]

That PSU looks like a gutless wonder. Probably only good for 400 watts or so before it starts shiting the bed. Get a quality PSU if you're going to try mining.

Edit: yeah... An "850w" PSU with a 380w capacity on the 12v rail? That should have tipped you off. Hopefully it didn't damage any hardware when it self destructed.

[rudyo]

I use this one, or I use nothing.  Good for 4 7950's or 4 R9 280x. 

http://www.newegg.com/Product/Product.aspx?Item=N82E16817151109&Tpk=seasonic

[carlb007]

That PSU looks like a gutless wonder. Probably only good for 400 watts or so before it starts shiting the bed. Get a quality PSU if you're going to try mining.

Edit: yeah... An "850w" PSU with a 380w capacity on the 12v rail? That should have tipped you off. Hopefully it didn't damage any hardware when it self destructed.

It didnt tip me off because i didnt look at the amp ratings until AFTER it blew.
It was 5 minutes old when it went! :p

Ill be honest - it was the cheapest PSU id bought to date. I have 3 other rigs running on 2 cards each atm with 850W psus no probs...but those PSUs cost me about twice as much as this one!
Its so long since ive done anything hardware related i just started diving back in a month back when it all kicked off. Last time i built a PC before now was when the Geforce 2MX first came out must have been 11 years ago now...jebuz. Infact one of the old cases i dragged down from the loft id actually spray painted the DVD drive BLACK because back then you couldnt get em in black without paying twice as much :p

Cheers for the tips etc though. Ill send this POS back and claim DOA.  TBH if they title something as SLI then you would assume it would work regardless of my naivity!

Thanks.

[DrG]

That's not a 850W PSU.   It's not even a 400W PSU.  It barely has 384W for the 12V rails (2*16 = 32A * 12V = 384W).  My Antec HCG-400 puts out more power on a single rail.

Don't waste time trying to figure it out.  If you hooked each rail up to the PCIe connector you might be able to run the 7950 off of it with a low end system.

Buy a name brand or OEM quality PSU from Seasonic, Corsair, Delta, Enermax, Coolermaster (their higher end ones).  It doesn't need to be gold or plat.  But it needs to have most of the power on the 12V lines.

[Feneusens]

Hi all.
Just looking for some advice here as im not sure whats happened. I have/had a  850watt powercool psu (see here: http://www.scan.co.uk/products/850w-psu-powercool-pcpc850auba-80-eff-80-plus-sli-crossfire-eps-12v-quiet-fan-atx-v22)
I just setup a new rig with 1x R280X and 1x 7950 graphics card in (from a powered riser card). The PSU only has 2 8pin PCIE power connectors edspite being titled as SLI, so i plugged in as follows:
1x8pin into the 280x
1x6pin into the 7950
2xmolex to 8pin pcie for the 2nd power slot on the R280X off 1 cable coming from the psu
2xmolex to 6pin pcie for the 2nd power slot on the 7950 + 1 molex to the pcie riser card off the 2nd cable coming from the psu.

the 2 12v Rails were rated at 16A which should be 190W.

I plugged in, powered up, started mining just fine. Both cards running. I then changed the power-tune in config file from -20 to -10 via RDC, and suddenly heard a 'POP' in the other room. Went to inspect and the entire machine was off. Unplugged everything and turns out the fuse had blown in the power cable.
Swapped power cable over and just turned the psu on (not plugged into mobo) and 'POP'. Blew the 2nd fuse in the new cable.

Basically the PSU is dead - but what i wanted to know was - have i caused this or was i just unlucky with a faulty unit? What should normally happen if you over load a psu would it smoke up - id expect them to have some sort of resettable fuse in them.
The 2 cards should only be a max of 500watts (less because powertune was still -10%) but im not sure if its because i then utilised the riser on the same channel or what? - didnt actually need the riser in this case i was just testing it but a bit nervous about trying a riser on any of my other boards now - i bought 5 with the hope of adding a 3rd card to my other boards. What power supplies does everybody use or recommend for 3x280x or 3x7950s? Do any exist with 6 pcie power cables or does everyone utilise the molex adapters like i have?

thanks in advance!

The quality of the PSU is really bad. Try getting brands like corsair and seasonic.

[Noruka]

Hi all.
Just looking for some advice here as im not sure whats happened. I have/had a  850watt powercool psu (see here: http://www.scan.co.uk/products/850w-psu-powercool-pcpc850auba-80-eff-80-plus-sli-crossfire-eps-12v-quiet-fan-atx-v22)
I just setup a new rig with 1x R280X and 1x 7950 graphics card in (from a powered riser card). The PSU only has 2 8pin PCIE power connectors edspite being titled as SLI, so i plugged in as follows:
1x8pin into the 280x
1x6pin into the 7950
2xmolex to 8pin pcie for the 2nd power slot on the R280X off 1 cable coming from the psu
2xmolex to 6pin pcie for the 2nd power slot on the 7950 + 1 molex to the pcie riser card off the 2nd cable coming from the psu.

the 2 12v Rails were rated at 16A which should be 190W.

I plugged in, powered up, started mining just fine. Both cards running. I then changed the power-tune in config file from -20 to -10 via RDC, and suddenly heard a 'POP' in the other room. Went to inspect and the entire machine was off. Unplugged everything and turns out the fuse had blown in the power cable.
Swapped power cable over and just turned the psu on (not plugged into mobo) and 'POP'. Blew the 2nd fuse in the new cable.

Basically the PSU is dead - but what i wanted to know was - have i caused this or was i just unlucky with a faulty unit? What should normally happen if you over load a psu would it smoke up - id expect them to have some sort of resettable fuse in them.
The 2 cards should only be a max of 500watts (less because powertune was still -10%) but im not sure if its because i then utilised the riser on the same channel or what? - didnt actually need the riser in this case i was just testing it but a bit nervous about trying a riser on any of my other boards now - i bought 5 with the hope of adding a 3rd card to my other boards. What power supplies does everybody use or recommend for 3x280x or 3x7950s? Do any exist with 6 pcie power cables or does everyone utilise the molex adapters like i have?

thanks in advance!

i have machines running a 860W with 3x R9 280x and that PSU works like a charm 24/7 for months now. My guess is you didn't buy a certified PSU and went with a cheapo one. PSU should never be skimped on in any mining rig.

[DrG]

i have machines running a 860W with 3x R9 280x and that PSU works like a charm 24/7 for months now. My guess is you didn't buy a certified PSU and went with a cheapo one. PSU should never be skimped on in any mining rig.

Don't need to guess. Look at that thing.  Green LED and 2 16A rails.

Even my Antec SmartPower 350 from 2003 has 17A/15A rails.

[vadoff]

Notice how Powercool is dead last in this PSU Tier list? (click see full content, first post) http://www.tomshardware.com/answers/id-1804779/power-supply-unit-tier-list.html

Yeah. Consult that list, and also this one too before buying a PSU in the future: http://www.eggxpert.com/forums/thread/323050.aspx

[DrG]

Notice how Powercool is dead last in this PSU Tier list? (click see full content, first post) http://www.tomshardware.com/answers/id-1804779/power-supply-unit-tier-list.html

Yeah. Consult that list, and also this one too before buying a PSU in the future: http://www.eggxpert.com/forums/thread/323050.aspx

I generally agree with that list, but a few of the brands they put on the avoid list have some decent PSUs.  Inwin made awesome cases back in the day and decent PSUs.  Rosewill is on the avoid list.  Rosewill is Newegg's house brand.  Most of their cheaper stuff is pure crap, but the higher end stuff is decent but may have premature failures.

JohnnyGuru is an awesome reference for PSU reviews.

[draceus]

I would always at least try to get a PSU with minimum of bronze+ certification so you know that it will be close to the amount of watts you purchased.

[CounterStrike]

Get a gold quality PSU instead of some 80% + effiency...

[GoldSeal]

you can likely fix that psu by opening it and installing a new thermal fuse. In the future, try not to use more than 80% of the rating. You likely have a dual rail PSU and overheated the smaller rail.

http://www.techrepublic.com/article/learn-to-re-fuse-a-power-supply/