i have CS:S and im on a amd athlon xp 1600 (1.4ghz) 256mb ram 64mb radion grafix card and mine runs fine as long as nothign is on in the background perfectly fine only thign slows me dwon rarely is if my wireless network starts playing up so mayeb its not a hardware problem or in CS:S go to options video advanced and edit some of the settings to a bit lower then try