I have a Asus P4B running Win XP Pro with 2 X512 mb PC133 ram. One memory stick crashed. I can replace it with a generic chip for $16 free shipping. The other 512 Stick is good Corsair and runs XP just fine. I only use this computer for email and some spreadsheets and a few other programs but nothing strneous. Should I get another stick or just stick with 512MB. Had this computer since XPcameout. Never a minutes problem. Runs great even on 512MB