DOOM 3
Our usual graphics test with DOOM 3 is to run it in high-quality mode. It looks damn fine, too. However, to get the best eye candy, although the difference above HQ mode is barely discernible, Ultra quality is the one to run with. Ultra quality uses no compression when loading specular and diffuse maps, and, as a consequence, it's reckoned that up to 500MB of texture data is needed. Sounds like the perfect recipe for establishing the worth of cards equipped with a 512MB framebuffer, doesn't it?
Running Ultra quality on both 512MB and 256MB RADEON X800 XL cards yields no meaningful frame-rate increase for PowerColor's card. The results go in the face of the theory discussed above. The reasoning as to why there's so little difference has more to do with how DOOM 3 uses textures and vertex data. On most single areas the game barely uses 256MB of data whilst rendering. id's intelligently minimised the case where areas will require heavy texture loading/dumping. The tested, inbuilt Timedemo 1 represents a case where there's little need for more a frambuffer larger than 256MB, hence the near-identical scores.
The same is true when discussing 4x AA/8x AF.
