The highly-anticipated Half-Life 2 game will have a major bug with current DirectX 9.0 hardware resulting in impossibility in enabling Full-Scene Anti-Aliasing, a popular feature that dramatically improves image quality in games. Apparently, there is a limitation in DirectX 9.0 and/or DirectX 9.0-compliant hardware that will not allow the function to be enabled on certain graphics cards if the workaround is not found.
According a Valve officials quoted in forums at the HalfLife2.net web-site, there are problems with the way that current hardware implements FSAA. If you enable it, you will see a lot of artifacts on polygon boundaries due to the way that current graphics processors sample texture subjects with FSAA enabled.
Valve continued that this is a problem for any application that packs small textures into larger textures. The small textures will bleed into each other if you have multi-sample FSAA enabled. Currently both leading graphics chips designers use multi-sampling or hybrid multi-sampling + super-sampling methods to for FSAA.
News source: X-bit labs
