Ok, I have a dual boot setup. System specs are:
Core2Extreme QX9650
DFI Blood-Iron P35
PC Power & Cooling Silencer S75QB 750W PSU
4gb Crucial Ballistix DDR2-800 (Micron D9)
Visiontek ATI Radeon 4850
BFG Physx card
74gb WD Raptor (XP) / 160gb WD Enterprise (Vista Ultimate x64)
(2) 320gb SATA WD hard drives in RAID-0 (media storage)
Now, in XP I run Crysis at 1680x1050, 8x AA, and everything on high; and the game plays perfect. I rarely notice any lag.
In Vista 64, I tried running Crysis at the same specs except at very high and got a slideshow. Dropped it down to 4x AA and just high settings & it made it playable, but still a little slow.
What gives? Is it DX10 putting more stress on my system? I figured the 64 bit would help the game as it can actually take advantage of my CPU more… no?