Half-Life 2: Episode One
The Radeon X1950 XTX is less than 10% ahead of the Radeon X1900 XTX but this is just enough for it to catch up with the GeForce 7900 GTX in resolutions higher than 1280x1024. It is possible to play with enabled 4x FSAA even in 1920x1200. The more expensive GeForce 7950 GX is not actually needed for that, although it ensures a higher min frame rate.
Prey runs on the Doom 3 engine and uses OpenGL, but the Radeon X1950 XTX isn’t any worse than the GeForce 7900 GTX here and is 15% ahead of the Radeon X1900 XTX (and this difference in speed is only due to the difference in the memory clock rate of the two cards: 1000 (2000) MHz against 775 (1550) MHz). The GeForce 7950 GX2 defaults from this race, betraying one of the downsides of SLI technology: it needs support for the particular game in the ForceWare driver to work correctly.