Finally a well coded game ! My congratulations to the developers.
Under XP, 1280x1024, 16xQ AA, all options set to super high, & i'm getting 120 fps (sometimes peaks of 180-200 fps).
Under Vista x64, with DX10, it runs slower, a lot of zones under 60 fps. Even with DX9 the performance is worse than on XP (perhaps 50% slower with DX10 & 25% slower with DX9)