Found these 9.6 drivers. These are not official yet and have not been released by ATI and my not be final version. Ive installed them though and had big jump in GTAIV fps. Other people have said its fixed Warhead for some people who had "stuttering" & works better with ARMA2.
ATi Catalyst 9.6...
arma2
ati
catalyst
community
compatibility
drivers
feedback
fps
gaming
graphics
gtaiv
non-official
pc gaming
performance
stuttering
system performance
tested
update
video drivers
warhead
