Hi Jabba,
there are some settings in Arma you dont need for good looking graphic:
set:
Postprocessing to low
object detail to very low
landscape to low (not very low to see grass)
AA disabled (if you play 1600x1200)
the rest to high/very high
I play 1250x960, 1200m viewdistance, all high/very high, AF middle and the rest (postprocessing etc low/very low) in the wood with 30-35 fps and the start scene (rhamadi) with 120 fps.
my AGP-Sys:
Gecube 1950XT @ 715/827
X2 4200 @ 2,9 Gig
2 Gig MDT
sry for my english,
regards from germany
EDIT: HD-performance has no influence on game-performance!