Originally Posted by agentkay
The only exception was DX10-64bit, that one dropped the average by 5frames (9 out of 10 runs) but one time it was actually just as fast as DX10-32bit/DX9-XP. I don't know what happened in that one run.
Did the test again, and this time it was 5 out of 5 runs (DX10-64bit) that were just fast as DX10-32bit and DX9-32bit (XP). DX10-64bit seems to be very sensitive to some settings in the driver which can hurt performance and apparently a reboot can fix it. 2GB seem to be enough with all settings on High (in Vista64) because memory usage was around 70-80%