Yes you can do it easily, my friend has his Sapphire 9800pro 128mb overclocked from 378-676 to 470-800, and that`s really great, he is using Arctic Cooling Vga Silencer Revision3(high rpm) without memory ramsinks, pretty cool memories at 800mhz. Mine Msi 9800pro 128mb is overclocked to 425-724, my memories are really hot as hell also with ramsinks, I have to max up my Thermaltake case fan regulator to highest level, when I am going to play games because without that I am getting artifacts after a longer time of gameplay. It`s pretty loud in gaming mode. Pick up 9800pro 128mb with no fear, but only one with 256bit memory interface!!! By 256bit Sapphire 9800pro 128mb, but beware of low price of this card, it should be probably cripled 128bit version, really be hardly beware!!!.