I have two reference 6950s with my 955 at 4.0. On CPU intenstive games (ie BF3) it is my understanding that you will see a lot of FPS spikes, especially in Multi, with any amd processor (quads more than hexes). However, for less CPU intensive, but still graphically intensive (Ie Metro 2033), my 955 is only used roughly 50%, while both 6950s are pinned at 99% (with all settings maxed). As mentioned before in this thread, there are a lot of problems with CF that you should avoid if you can (Ie dont buy two right off the bat). For example, in GTA4, i have to disable CF for it to even boot, and it ran better when I just had one card imo (yes i realize its terribly optimized). I know other games have trouble as well, and driver support is often spotty, not to mention your limited upgrade path if you buy two lower end cards. Another vote for the 6950
did i mention 6950s are beast?