In order for you to play S.T.A.L.K.E.R.: Clear Sky on Windows with minimal graphics settings, your computer must meet the following requirements
Supported OS:
Microsoft® Windows® XP(Service Pack 2)/Microsoft® Windows® 2000 SP4
Processor:
Intel Pentium 4 2.0 Ghz / AMD XP 2200+
Graphics:
128 MB DirectX® 8.0 compatible card / nVIDIA® GeForce™ 5700 / ATI Radeon® 9600
Memory:
512 MB RAM
Sound:
DirectX® 9.0 compatible sound card
Hard Drive:
6 GB free hard disc space
In order to play S.T.A.L.K.E.R.: Clear Sky on Windows with maximum graphics settings, you need a computer with a configuration no worse than the following
Supported OS:
Microsoft® Windows® XP/Vista (SP1)
Processor:
Intel Core 2 Duo E6400 / AMD 64 X2 4200+
Graphics:
256 MB DirectX® 9.0c compatible card* / nVIDIA® GeForce™ 8800 GT / ATI Radeon® HD 2900 XT
Memory:
2 GB RAM
Sound:
DirectX® 9.0 compatible sound card
Hard Drive:
10 GB free hard disc space