If you are talking strictly about an OC in Hz, then it is obvious that the P4M 1.4GHz is the best, OCing 1.6GHz+ over its stock 1.4GHz. I'm not exactly sure what the core clock of the 1700+ is, but assuming its just above 1.4GHz, it comes close to the healthy OC the P4M had in Hz. But if you are looking for the best OCer with respect to stock speed, you have to look at the OC as a percentage. In this case the old Celeron has it, as a 566MHz @ 1.2GHz is a 112% OC. I heard someone else mention that the 1700+ had about the same %OC. If that's the case, then the 566MHz Celeron was capable of running 2.12 times as fast as its stock speed, and the 1700+ was capable of similar feats. So with respect to their srock speeds, these were the best OCers.