As Daven said, the gains you'll get for the price you'll pay simply won't be worth it at all. DDR prices are sky high, a good set of PC3200 will be fine for getting solid performance. I've always been into the fastest memory and pushing it to the limits, but even I'm using a cheapo set of PC3200 2x1Gb overclocked mildy. On S939 the memory bandwidth isn't important in gaining the best performance, its all about CPU speed.