Here's something else odd to think about. I have two X1900 cards in Crossfire configuration with an FX57 at 3ghz and 2 gigs ram. I get LESS FPS when running both cards in Crossfire compared to only 1 all by itself. Unbelievable. My system is stable in Crossfire mode verified by endless hours of BF2 and many loops of 3DMark '05. Nothing like spending another $500 to get less FPS. Something has got to be going on with the R580 in these X1900 cards. This review showed this clearly with the X1800 outperforming the X1900 at lower resolutions.
It's nice to see that 8xAF doesn't hurt performance really at all. I've tried running everything on high settings with 8xAF at 1920x1200 and I get about 25FPS. Running the same settings with only 1 X1900 card gives about 30FPS.
ATI or GRIN need to get on the ball with these issues because the 7900 GTX's in SLI configuration using alternate frame rendering seem to almost double their FPS when compared to only 1 card.
Luckily this game doesn't require 60+FPS to be playable. The very slow movements of the players will likely allow most of us to handle 30-40FPS as playable.
If this ATI issue isn't resolved soon, I'll be switching over to the 7900 GTXs since the X1900 have quite a nice resale value on eBay.