You need a new mobo. Intel isn't like amd. You need new mobos for the newst pentiums. Some old 755s will not support new pentium 4s. That is just the way it is. Also, check Xbit labs. They have something about the pentium ds. Apparently, then 2.8 can oc to 3.3, but after that, the processor becomes unstable. Finally, clock speed does matter. Check the benchmarks.