I finally went and upgraded my video card, mostly to play Mechwarrior Living Legends (a Crysis Mod).
Currently using HIS 3850 ICEQ3 AGP. My aforementioned system now runs Demigod smoothly at 1600 x 1200 on high. This system also runs the Crysis Demo at 1280 x 1024 on high with barely a hitch (turning a few settings to medium makes it run perfect)
The only downside is I feel that I may have failed you a bit as a beta tester. Until I replaced the card, I had not looked at impulse to see if there had been an update since October. I also found out that my Dx9 drivers were slightly out of date.
As such, it may be that my x800 would have been OK (probably not at highest settings). Another thing that indicates that my old card might have worked is that I attempted the October version of demigod on the new card before I checked impulse, and encountered a frozen load screen when I launched a game. The new menus are nice, and the load times have been a bit slow, but not insufferable.
Anyhow, please accept my apology for being unmotivated to rip the brand new card out of my system (risking static from one of the 2 walking furballs in my home), in order to put the x800 back in and see if demigod is now optimized for it.