[DiabloD3]

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.

[SilasX]

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-...

[hippich]

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 :))