S.T.A.L.K.E.R.: Clear Sky

Publisher: Deep Silver

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.





The improvements resulting from the increased clock speeds on the HIS Radeon HD 4870 1GB IceQ4+ Turbo amount to a five percent performance enhancement at 1,680 x 1,050 0xAA 16xAF with high in-game details. This makes HIS's card around six percent faster than Nvidia's similarly priced GeForce GTX 260-216.

At higher resolutions, the frame rates become less playable - around 30 fps is fairly acceptable in Clear Sky - but the HIS Radeon HD 4870 1GB IceQ4+ Turbo's increased clock speed means it delivers a reasonable experience at 1,920 x 1,200. The additional memory bandwidth pays dividends for the minimum frame rate in particular - it's four fps higher than what the reference 4870 1GB achieved.