It is common knowledge that Stalker: Call of Pripyat offers a DirectX 11 rendering path. PC Games Hardware shows where the new API is used to increase either the fps or the visual quality.
Stalker: Call of Pripyat - The Engine
Like its predecessors Call of Pripyat is based on the X-Ray Engine. Version 1.6 offers diverse SSAO modes, like High Definition AO and Horizon Based AO including Motion Blur. In addition there are impressive textures which appear very realistic due to Bump Mapping and Steep Parallax Mapping - especially in combination with Wet Surfaces. The dynamic Deferred Lighting (God Rays, Bloom, adaptive Tone Mapping etc.) with fluid Day Night Cycles and varying weather conditions (rain, lightning) is extremely realistic once again. The indoor levels are very atmospheric. Due to DirectX 11 Stalker: Call of Pripyat offers Hardware Tessellation (delivering more detailed NPCs) and Contact Hardened Shadows. Besides that the DirectX 11 graphics look just like the DirectX 10 version. But the way of how the Post Processing effects are calculated is different, too: DirectX 11 uses Compute Shader to some extent. Stalker: Call of Pripyat - Hardware Tessellation
If you use a Radeon graphics card of the HD 5000 generation, Call of Pripyat offers "Tessellation2 in the graphics options. In order to make this option show up, you have to activate the "Erweiterte dynamische Objektbeleuchtung (DX11)" (enhanced dynamic object lighting) first. After that most figures in the game are displayed with a much higher level of detail since more polygons are calculated. The comparison below demonstrates the difference between DirectX 11 with and without Tessellation.
Stalker: Call of Pripyat - Benchmark sequence and results
For our benchmarks we use a short sequence on board of the Skadowsk, a stranded ship that the Stalkers use as a camp. In this scenario we walk through corridors into the habitable room where about a dozen Stalkers are eating and chatting.
Without Tessellation Call of Pripyat runs in DirectX 11 about 20 percent faster than in DirectX 10 -depending on the scene the benefit can vary between only 10 and even 40 percent. If you activate Hardware Tessellation, the framerate drops drastically and DirectX 10 is faster than DirectX 11.