Performance in First-Person 3D Shooters
Both the Gigabyte cards deliver the same performance of over 120fps at the beginning, but the Radeon-based one comes out on top in 1600x1200, obviously due to its more advanced memory subsystem.
Here, all the cards provide a high enough average frame rate when we turn on 4x FSAA. The game was tested with the Fraps utility, so the numbers may be somewhat inaccurate.
The Chronicles of Riddick
The Gigabyte GeForce 7900 GTX beats the Gigabyte Radeon X1900 XTX in this test, but it is greatly aided by the design of the game engine which uses OpenGL and stencil shadows. Anyway, this advantage matters little here because both the cards deliver an excellent average performance in all the standard resolutions even with enabled full-screen antialiasing.