Besides the AVC Sunflower, the Thermaltake Volcano 478 seems to be the best. The Sunflower has about a 3 degrees C advantage at full load on the Thermaltake, but the Thermaltake is considerably more quiet (just slightly louder than the P4 stock HSF, and about 6 deg celsius cooler than the P4 HSF at full load). So, for best performance, go with the sunflower. For good performance and relative quiet, go for the Volcano. Both the Thermaltake Volcano and the AVC Sunflower are affordable. You can get either for less than 20 bucks shipped, online.