From what I understand, I thought SLI was supposed to make one card out of two, so that games wouldn't even notice. Anyway, the X800XT is AGP, unfortunately.
Otherwise: My Abit mobo has a PCI problem. When a PCI slot is used, CPU load is constantly much higher than usual. A BIOS flash fixed it. Now Quake 4 runs at 1600x1200, Ultra Settings, AA 16x decently, and Halo runs well, too. Aquamark went up from 30,000 to 84,000. Still a tiny bit of annoying lag in Quake 4, but at such unbelievably high settings, I would say mission accomplished, anyway, aye?
Thanks for the help.