recommended settings are 2.5 ghz processor / 512mb ram / a good graphics and with directx 9 level.. but mine is 2.6 ghz and pretty smooth for cs and 8800 gt nvidia pretty clean.. no lag even in cs since i got my computer..
heres the best advice you'll ever get about CS:S... IT SUCKS !!! had CS for a long long time, and trust me when i say this...if your a fucking n00b gamer, then CS:S is proably for you...but is it worth getting a new pc, or a new gfx card for ?..hell no...its not....dont wast your money gfx are nice, but the game play is poor, and its to easy....simple. source sucks...1.6 is still the best online 1st person shooter around, and its still the greatest online first person shooter ever made... source is basically for kids with no skill or game sense.