S.T.A.L.K.E.R.: Clear Sky is the prequel to GSC Game World's sleeper hit S.T.A.L.K.E.R.: Shadow of Chernobyl and was unfortunately released in a bizarrely unfinished state and it's taken some time for the game to reach the levels of stability that we expect from a game. However, with the new 1.5.07 patch, Clear Sky runs great and as you would expect it to.

Clear Sky uses a heavily tweaked version of the X-Ray engine, which debuted with Shadow of Chernobyl and was updated to support several new graphical effects using DirectX 10 (and later DirectX 10.1 through the 1.5.06 patch). The improvements include enhanced visual effects like 'God Rays', wet surfaces, volumetric light and smoke, depth of field blurring, and screen space ambient occlusion lighting as well as better textures.

We used a custom timedemo for our testing, which incorporates many of the advanced effects introduced with DirectX 10 – we also enabled DirectX 10.1 on the Radeons. However, due to the intensity of engine, we have set the in game details to "High" instead of "Maximum" and have left anti-aliasing disabled for the time being.






At 1,280 x 1,024 and 1,680 x 1,050, the Sapphire Radeon HD 4890 Vapor-X 2GB, just like in Crysis, managed to pip the Sapphire Radeon HD 4890 1GB Atomic to the post by a few frames per second although at 1,680 x 1,050 the difference was negligible. At 1,920 x 1,200 the difference is more pronounced with the Atomic posting a clear lead but there's little between the two graphics cards at 2,560 x 1,600. Either way the Vapor-X is able to hold its own all the way up to 1,920 x 1,200 with room to spare making it a great choice for owners of 24in monitors out there.