It's called 'hot and cold aisles' and it's been 'extreme'ly effective in most datacenters for one reason: it's dead simple.


  HOT ||  rig  ||  COLD || rig || HOT
  HOT ||  rig  ||  COLD || rig || HOT
    < air     <  air      air >   air >

Exhaust the HOT aisles properly and you've solved your problem.

The molex adapter will supply whatever power the card needs, up to the limit where it catches on fire anyway

Use the molex connector closest to the PSU to minimize electrical losses.  As long as your molex cables are a large enough gauge to support the power draw, and the PSU can supply it on that rail, you'll have no problems at all.

The extra pins in the 8pin connector simply add another 12V wire to "spread" the current draw and avoid burning up wires.

As long as your adapter/molex aren't getting hot, you don't have to worry about that.

Maybe the clipped grill?

I bet if it was sold as new-in-the-box canary would've made a killing.   People devalue things weirdly.

I knew I should've bought a second ticket!

Congrats mike, sorry for the lame-o proceed canary.  That was good fun

Ahh, sorry misunderstood since you were talking about isolation.  There's really little danger of voltage spikes over the power switch pin - when was the last time you saw or heard of a fried PC power button?

A diode on the transistor base pin would keep it pretty safe I think, but diode+transistor is pretty similarly priced to your SSRs unless you're buying them in bulk anyway.

Good luck to you, it may be slightly overengineered for the purposes here, but I wouldn't dare kit whatever I'm about to cobble together here with transistors, you're in a better spot for it

What SSRs are you getting so cheap?  When I was looking for these it seemed impossible to find something that could handle >6A for any reasonable price..  how much load are yours rated for on the AC side?

Those pads are probably more for protection than thermal transfer, it doesn't look like that would really do much to cool the memory.

Make sure you haven't scuffed any of those chips deeply or broken any traces on the bottom of the card when you removed it..

I don't know about the MX2 but most things thermally conductive are electrically conductive at some threshold.. the 0.8-2V around a CPU might be fine, but maybe accidentally shorting a 12V to ground overcomes it's resistance..

Unless you removed thermal paste when you took the backplate off, I don't think you need any on those memory chips, and you likely don't even need the pads.

I'd clean it carefully and thoroughly and try the card again.



Ah, yeah I haven't had any dual-gpu cards personally, didn't know it was a thing.

No shit, one of these stores opened up just around the corner a few months ago, I had no idea they carried this kind of stuff.  Might have to go 'browse' later

Could you tell us what model 5970 you have?

Maybe show us a picture of what you're referring to?  I haven't seen any cards yet with backplates, but there are lots of cards out there..

I've been running into this a lot lately, I wasn't aware it was a problem at all but it could explain the odd locks I get every once in a while..  my multimeter vanished so i'm waiting for a new one in the mail to check this out

I was finally able to really research this some more and it seems like it's pretty trivial.

I'm looking at building mine this weekend with a Jennic ZigBee IC I happen to have.. it's way overkill for this but hey miners are good at utilizing whatever happens to be around in a pinch

I'm almost convinced that this could be done with serial cable + transistors alone just by pulling a serial pin high to trigger the transistor.  ~$5 in parts

That's a wise idea regardless of your situation.  I'm going to pick up a spare just for that inevitable 'the PSU is down' moment.

Does that 2nd PSU fire up if you just short the black and green without connecting it to anything else?

If not, that's pretty weird, I'd plug a multimeter between the green and black pins, you should see ~5V.  If not, the PSU may need some other load (like the 5V motherboard standby) in order to power on.  A heavy resistor on that pin to ground should do the trick if so, but I don't know which pin that'd be offhand, just the 5V rail I'd guess?

Eh, some people are just in it for the fun.  Some people just haven't discovered the benefits of open-air rigs with your GPUs on raised rails as well

Truthfully I was looking at a similar setup yesterday for some far off point in the future when I no longer want to mine with my 6950s.  Water cooling is the only way to keep 4 of them happy in a case, but I'm a bit put off by the prospect of needing 4 120mm radiators just for the GPUs.. the ridiculous bulk almost defeats the purpose of putting 'em in a case at all..

FYI, all your links seem to be broken

I don't know much about watercooling so I don't have a real answer to give you 

I think in the 'standard' overdrive switch position power draw from a 6990 is about 350W, 450W+ when it's turned on.

But your question was about 5970s, which should come in less than 350W each allowing room for a little overclocking.

Assuming that, with 4 cards you're going to be pulling potentially up to 1400W.  That's quite a bit on a single rig - and quite a bit for normal 15A household circuits in the US - which can handle about 1800W, and your wiring will be a bit warm at that load.

Do you have a model number for that PSU?  Looking at ratings for the rails will help us give you a real answer.

There's only one 'right place' for thermal paste, and the bottom of the card isn't it.  If you used a conductive thermal paste like Arctic Silver 5, you've probably shorted something out on the bottom of the card..

The only place for thermal paste is a very thin layer between the heatsink and the large GPU chip - nowhere else

If you don't have special cleaning solution, a lint-free cloth and 90%+ isopropyl alcohol works well to clean it off.

[edit] of course, 5970 has two GPUs, so a thin layer between each GPU chip and the heatsink

I highly recommend monoprice if you can wait a couple days for it - $0.95 for a 90deg cable.

There are also lots of other options: http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10226

I order all my sata/usb extenders/similar hard-to-find-cheap adapters and cables from them, never let me down.

All the green ones are 5830s, orange and red are 6950s.  You'll notice how the cooling on the 6950s blows, no pun intended.

There's a reason this is in the gambling forum

Unless all the tickets get picked up in the next couple of days, my chances are pretty good too, and poor Canary will end up selling his card for half what it's worth anyway