It seems as if the 4650 is the better choice. I read about 50+ reviews telling that the idle temperature is 70 degrees Celsius and about 90 degrees Celsius during game play. If the radeon 4650 can only play about 2 hours before crashing and the radeon 4550 can play 4 hours.. I would rather choose the 4550 because it lasts longer(I'll play less demanding games so they'll look all the same LOL)