I got Asus EN8800GTX and I never had any serious problems. I am running Arma at "high" in every setting except shadeing (low), on resolution 1600x1200.
Only problem I have is that LOD isnt as nice as when I play on other PC with 1900xtx. 8800GTX LOD is like... well pollution in the air. Its "foggy" and all. While in ATI card its crystal clear.
[My pc is FX-60, 4 gig DDR Ram, Windows XP pro]