To those with multi-5970 setups: which mobo are you using?

[bitcool]

I guess this is the case. I have tried researching a PSU that supports x4 5970s but haven't really found anything that is conclusive. There just isn't any info out there.

If I had to toss a coin, I'd say that a 1200 Watt Corsair or Antec might do it.  Might.  However, it appears you are using the MSI 890FXA-GD70 motherboard.  Though it has five PCI-E, they appear stacked right next to eachother.  I tried TWO right next to eachother in my MSI Big Bang, which has as many or more slots, and found that putting cards in two adjacent slots caused the heat to go WAY up, perhaps 10-15 degrees on each card, causing malfuncitions.  The clearance between the cards is minimal, so I have no idea whether aftermarket cooling is an option.  I had to space the cards out enough that I don't think I could get a third one in there without more spacing between the slots.  If you get 4 cards in one box working reliably, please say what the trick is.  I noticed about 91 degrees is about where my 315khash begins to fall apart on each core.  Also, I did find that things run well at 99% GPU, but when I get to 100% GPU it falls to about 200khash/second momentarily until it drops to 99% again.  This is due to the increased heat just a couple of degrees above 91 C.  If I turn the clock DOWN, the GPU will cool, stay at 98-99% and give me a consistent 315khash again.  If you get higher numbers, let me know your settings.

What I have done when I tried 3x 5970s was to not screw them into the case, and stick pieces of a plastic drinking straw in between the gpus in order to create room for airflow. ...This is from blog.zorinaq.com. Sorry for the insanely big picture. 

The air intake port is on the other end of the cards, so you don't need to put spacers on this end. that will relieve some stress on the PCI-E slots.

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[Steve]

It's not a power supply issue...I'm having the same problem with the same mobo and I have a 1200W PSU.  I've seen others on the asus forums with the same issue too.

[ronaldmaustin]

It's not a power supply issue...I'm having the same problem with the same mobo and I have a 1200W PSU.  I've seen others on the asus forums with the same issue too.

What brand and model?

[Steve]

It's not a power supply issue...I'm having the same problem with the same mobo and I have a 1200W PSU.  I've seen others on the asus forums with the same issue too.

What brand and model?

I have the Antec 1200W.

[snedie]

How have you managed to get your temps so low on such a high clock/vcore? I'm guessing your not running the stock cooler...

[mrb]

OMG, this is devastating o_O. Three disadvantages:
1. When you will be mining like for few months/years, PCIE slots will loosen and get damaged (because the cards are not properly inserted into the slots, they're bent). You will have to buy new motherboard then.
2. The slots will loosen even faster, if you make the case stand vertically. You have to put this horizontally to work.
3. When you start mining, this setup will overheat with 99,9% probability. This is not for serious solutions.

No, it does not overheat. GPU temps are between 65 and 85C. Throttling doesn't happen until ~100C. Shortly after posting this picture I slightly changed my setup by putting the spacers near the end of the card where the fans are, for more efficient cooling, and slightly less pressure on the PCIe slots. This machine has been mining for 2+ months 24/7.

-mrb

[snedie]

Dingus; With your new Mobo do you have to do the monitor swap trick to get the second card running or does it detect it as another thread? Whats your hash rates? Im getting some random dropouts and all my temps are pretty reasonable.

Dual 5970's on the P55-GD80 motherboard. I get the same temps as this with a 900Mhz clock, but my pc has it's side panel off, facing an open window with a desk fan blowing into it. You should lower your memory clocks to 500Mhz, this will save you a little bit of power and maybe 1-2c temp.

[max in montreal]

i have the 890fxa-gd70 board also.

I am using an x3 1000 watt psu. I can run 2 x 5970 and 1 x 5870 no problem. if i take out the 5870 and replace it with a 5970 the motherboard does not recognise all cards.