Ensure compatibility by checking your PC's operating system Windows XP, Vista, 7, 8, 8.1, or 10. Linux Ubuntu 12.04. or Mac (any OS X version) before downloading Counter-Strike. Additionally, allocate 2 or 4 GB of RAM and ensure approximately 370MB to 8GB of free hard drive space. The game's various versions have differing weights due to graphics, effects, and enhanced visuals.