Call of Duty
NVIDIA has always been the king with Quake 3 engine type games though both the ATI-based cards still pull in good framerates. The 6800 tanks however at 1280 and above with AA/AF due to memory limitations. The same effect can be seen in other 128MB cards. Neither the Sapphire X800 XL or the Gigabyte X800-256MB have this problem.
Jedi Knight2: Jedi Academy
Jedi Knight 2 does not seem as texture or geometrically heavy as Call of Duty so there is no sudden drop off for the 6800. Framerates are closer together but the 6800 series manages to stay on top. Again, the framerates for the Sapphire X800 XL remain very good and Quake 3 engine based shooters should remain playable up to 1600x1200 with everything on.