Been trying to tweak arma2 for a while as i have a fairly old rig, Athlon X2 4200+ OC'd to 2.6Ghz, 4Gig of ram and an 8800GTS.
Obviously it played like a dog at first but it's getting there slowly!!! I've tried just about everything including 1.03 to get to this point.
I have windows 7 on one hard drive, arma 2 on a seconf.
Just today i tried moving the windows pagefile to a third disk. Windows recommended 4822MB so i set it to that as a fixed size.
My FPS has jumped, from previously mid 10s (15/16/etc) near towns to a fairly steady 20+. I was shocked to finally hit 25 in the forests with my team running around me. The intro screen even hit 70 at one stage (barely got near 60 before) so i'm sure there's a boost in this tweak
I have shadows on v.high, textures on v.high, post processing on v.high and everything else on normal or low, at 1280x800. View distance is only ~1 mile though but it's better than nothing :/
This pagefile thing on a different disk might be worth a try for others?!?