so i just got another stick of 512 pc133 to go along with the other 512 pc133 stick i have theyre both the same manufacturer and should work together ..but for some reason whenever i put anytype of load on the computer it seems to freeze.. i can leave it at the desktop and it'll be fine ...also if i only put in one or the other it won't freeze it'll run eveyrthing fine...and i know its not overheating because the computer runs at a cool 43C (athlon xp 2000)....