All results are from the ARMA 2 demo benchmark, running the latest June 19 Nvidia drivers, WinXP, 3Gb RAM, SB X-Fi and a TrackIR4 connceted.
Using the default "very high" quality settings, 1920x1200, 10000m draw distance.
Core2Duo E8400 @3Ghz, Nvidia 8800GTS 320Mb RAM - Avg FPS : 12
Core2Duo E8400 @3.6Ghz, Nvidia 8800GTS 320Mb RAM - Avg FPS : 14
So got a 2fps gain from the overclock.
Core2Duo E8400 @3.6Ghz, Nvidia GTX285 - Avg FPS : 27
Thats a pretty big difference :)
Just messing around with the mission editor, its pretty playable around the village. Zooming in with the sniper scope - its jerky (low fps) for a couple of seconds and then settles down. Not sure if this is "realism"/design or it having trouble loading textures.
But damn, its a pretty game. And the motion blur is so cool.