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by ksadeghi 5298 days ago
It looks like they have 7 cards in there. If all the GPU's in that system where pegged at 100% for 30 minutes that system would overheat. There isn't enough space between the cards for free air flow.

7 x 5970's would give you just under 35 Teraflops instead of 12.

2 comments

To be fair, 5970s are dual GPU cards and would probably overheat packed in like that. 5970 have two 5870s, but are downclocked so the performance is closer to two 5850s.

8 5870s packed into two cases would survive if you keep the cases closed and put 3 Delta AFB1212s in the front pushing all the air through the cards and out their rear vents, this is how most Bitcoin miners build cases.*

If done right, 8 5870s should easily be kept under 85c even when marginally overclocked.

* Large scale Bitcoin miners have a habit of not using cases and use flexible risers to keep the cards away from each other out in the open. I do not recommend this as you lose out on high pressure cooling, a staple of enterprise/high performace computing.

FWIW, I set up a bitcoin mining rig with four 5870s by using liquid cooling. Full story here: http://silasx.blogspot.com/2011/12/exclusive-silass-bitcoin-...
I used water cooling. With 5970 it do not adds too much to price, but helps keep cards cool in tight environment. Specifically, I had microATX case with two 5970 at 850 Mhz (it could handle more, but just wanted to feel safer). GPUs were staying at 55-65 C. I bet you can do better if you route separate water tubes to each card (which I did not because of tight environment and being lazy :))

Before adding water cooling - it would lock after 30 minutes of mining at standard 725 Mhz.

This system worked very well for ~4 months (and then I sold it to guy from Alaska, since it became too hot in Texas :))

They have thermal image camera video:

(http://fastra2.ua.ac.be/?page_id=53)

They claim "slightly over 60 degrees".