I was planning to try a two via risers and two in the slots configuration and see what the temps are like. If it's too high, I'll go all with risers.
Thanks for the tip on headless. Yes, these will be headless linux rigs
Cheers
As long as you have good air flow, you should be OK. I'm actually running two 5850s in the x16 slots and in a case right now. Cards are pretty cool, but I have a lot of fans in the case, including a 230mm side fan blowing right on the cards.