Depends on what you want to spend. A few of the better ones are the Aerocool HT-101, Thermalright SI-97, Thermalright SLK-947U(be careful very heavy). The two Thermalright models need a fan purchased seperately. These three are on the high end of price but the SI-97 is probably the best for the money. This three are also all very big in size so they may not work. There are tons of cheaper models but be careful of noise. Most of these heatsinks have smaller fans running at very high rpm's which means lots of fan noise. Just about any of the aftermarket models will be better than stock.