STALKER
Because of its use of deferred rendering, STALKER's 3D engine only allows the activation of antialiasing based on shaders, which isn't very convincing and is difficult to use since the performance level is already low without, thus its absence here.
With or without antialiasing, the hierarchy doesn't change and the 8800GT finds itself to be the perfect middle ground between 8800GTX's performances (which are 18 to 25% higher) and those of the HD 2900 XT (16-18% lower).
