For quite a while now I have been using a latency adjuster utility to fix microstutters. I don't pretend to understand how it works but many flight sim fanatics swear by it and 180000 downloads from just one site can't be wrong:
http://downloads.guru3d.com/download.php?det=951.
Run it and set your video card to 64. (its probably at 128 or 256 as default).
I'm told (but not tried it) that you can cure some sound issues with this as well.
Spec:
AMD 4200 X2 64
Win XP up to date
2Gb
7800GTX
Audigy2
hope this helps someone
PS I get no stutters in SHIV
Phil