3x Crossfire 5970's?

bobtms

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Nov 29, 2010
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Please advise...

I was inspired by this guy's 6x Radeon 5970 machine:
http://www.youtube.com/watch?v=jR3QyoyIyig&feature=related

I wish to build a system with (3) 5970's that I already have along with an AMD 890FXA or 990FXA chipset motherboard that supports at least (3) PCIe slots @ x16, x16, x8 (e.g. ASUS Crosshair IV Formula, MSI 890FXA-GD70). I have +plenty+ of cooling through a special case I made and the room in which I'd like to install it has two sets of air conditioning units.

1) Radeons: I'm certain I have (1) Crossfire cable to connect a pair of 5970's, but what do I need to connect three?
2) Power: What are the power requirements? Rather than buy a super-expensive Silverstone 1500w PSU, can I use (2) 750W PSUs (1 PSU for two 5970s and 1 PSU for 1 5970 and the rest of the system)? For example, could I power up the PSU for the two 5970s, then power up the rest of the system? This would save about $200.
3) Chipset: What advantage is the 990FXA chipset (e.g. GIGABYTE GA-990FXA-UD7) over the 890FXA for such a machine? If I could use the 890FXA, this would save $80 or so.
4) Drivers: Any tips on drivers I should use for a Win7 or MS Home Server 2008 OS?

Many thanks for any advice.
 
You are going to have to take it up with the guy on that video. With normal CCC drivers, you cannot run 3 in crossfire. The maximum number cores you can run with crossfire is 4, which 2 5970's have. To go beyond that requires special hacked drivers I imagine.
 

bobtms

Distinguished
Nov 29, 2010
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18,510
Thanks!

Hmmm... some of these people seem pretty creative. This guy seems to be running (6) 58xx radeons, which would be the GPU equivalent, under Win7.

http://i.imgur.com/6s7zv.jpg

researching further...hoping for great insights from the community...