[Jelle]

Originally Posted by 8088 I was thinking of a limit in the benchmark, like fps_max in HL.

A card like AMD HD 6950 can deliver more performance than say a HD 6790, but it doesn't care about manufacturer. The same GPU, no matter RAM, clock speed or manufacturer will deliver the exact same performance in that game. An overclock gives max. an increase of 1 FPS whereas an overclock will give up to 10 - 20 FPS extra in other games.