I'm having lots of problems getting the twin GTX275 to run the RC5-72 under Gentoo 64. It seems to run for a little while then the thing just freezes and dies. The PC still runs OK crunching Wep-M2 or whatever its called.

Maybe the box is getting too hot? Ambient is anywhere from 30C to 40C. There are 2x Gigabyte GTX275 GPUs and Intel C2Q 9550 in an Antec 902 case.