Since your PC runs at max settings without any hitches when it comes to things like
smoke or fire in AHII, why don't you share your system details with us so we can all
get the same machine, v-card, etc.? 
Here's mine:
(Image removed from quote.)
we have very similar systems....
mine is AMD 2.9 GHZ also
except I have only 4 gigs of ram
and its a 32 bit system.....
I wonder what the differences are in how they run.....I want to upgrade to the 64 bit system, I need serious RAM
how long you been using the 64 bit? where you using 32 before? if so what is the difference?
is it just for gaming?
my rig is more for 3d modeling now and AH.....so I really could use as much ram as I can get......so 64 bit seems the way to go.