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 ""Ultra"" Mode 

Doom 3 was infamous at the time of release because the ""Ultra"" mode to run properly used more VRAM than was available on graphics cards in 2004. The Wiki article claims ""Ultra"" mode is unusable on <512MB video hardware. This is not true, and 256MB cards do run Ultra Mode at playable levels, albeit the Doom 3 menu does warn about running it on <512MB hardware.   "