There is no big difference between the two mainboards in Quake 4 , either, even though it is a recently released title. Theoretically speaking, the graphics subsystem with two GeForce 7800 GTX allows turning on even 16x full-screen antialiasing, but you may want to limit yourself to 8x FSAA to play in 1600x1200 resolution.
Serious Sam 2
This is such a demanding game that even the SLI configuration with two GeForce 7800 GTX gives you only about 50fps in 4x FSAA + 16x AF mode. If full-screen antialiasing of a higher level is turned on, the frame rate sinks below comfortable. As for the standings of the two platforms, we can’t see any difference between the nForce4 SLI and the nForce4 SLI X16 here just like we couldn’t in the tests above.