S.T.A.L.K.E.R.: Shadow of Chernobyl uses the ‘X-ray Engine’ to power the graphics. It is a DirectX 8/9 Shader Model 3.0 graphics engine. Up to a million polygons can be on-screen at any one time, which makes it one of the more impressive engines on the market today. The engine features HDR rendering, parallax and normal mapping, soft shadows, widescreen support, weather effects and day/night cycles. As with other engines that utilize deferred shading (such as Unreal Engine 3 and CryENGINE2), the X-ray Engine does not support anti-aliasing with dynamic lighting enabled. However, a “fake” form of anti-aliasing can be enabled with the static lighting option; this format utilizes a technique to blur the image to give the false impression of anti-aliasing. The game takes place in a thirty square kilometer area, and both the outside and inside of this area is rendered to the same amount of detail.
Benchmark Results: A single Radeon HD 3870 was able to run S.T.A.L.K.E.R. at 1920×1200 at 66FPS and a pair of Radeon HD 3870 video cards bumped that level up to 123FPS. This is an increase of 84.8% going from one card to two, which is great. With CrossFireX and three Radeon HD 3870 cores we were able to get 164FPS, which a 33% increase from two cards in CrossFire. Not bad scaling!