i have a ati 5870 2gb i have been having some problems with this card. first off i will get randon bsod while loading up mw2..i dont really know if this is caused by the card..i have updated drivers and uninstalled in safe mode...even uses driver sweeper to update the drivers...and i just noticed today...in dxdiag it says for my card that the approx. total memory is 750 mb....and my friends gtx 470 says that he has 4060mb...so i thought somthing had to of been wrong..
More about5870 edition problems
Have you tried other games too ? also what driver are you using ?