SuperAA performance scaling
We haven't had enough time with the Radeon X1800 CrossFire Edition to run a full spectrum of benchmarks with CrossFire's Super AA modes, but here is a quick look at its performance in Doom 3. Also present is a test system based on the Asus A8N32-SLI motherboard with the nForce4 SLI X16 chipset. This chipset's true dual 16-lane PCI Express slots have the potential to help NVIDIA's SLI AA work a bit quicker.

ATI wasn't kidding when they said hardware blending on the new CrossFire master cards would help with Super AA performance. The NVIDIA setups suffer a severe performance penalty for enabling SLI AA, while the Radeon X1800 CrossFire's drop-off is proportionally much lower.

Overclocking
Well, I tried to overclock the CrossFire systems using the automatic clock config utility in the Overdrive section of ATI's Catalyst Control Center. The app indicated a higher clock speed for at least one of the two cards (speeds aren't displayed independently for both), but, well, here's what I got for performance. Note that I've only labeled the overclocked Radeon X1800 XL CrossFire system as "OC." I know that the CrossFire Edition card was running its memory at a higher clock speed, but I have no idea about the Radeon X1800 XL.

We'll have to try this again with a future driver or a third-party tool that's more capable. Surely we could squeeze more performance out of an overclocked CrossFire rig.