theres a whole story about the pentium M
when the pentium 3 was dying out, intel had 2 options, continue on the P3 arquitecture with a shorter more optimized pipeline, which was the P3 tualatin, or make a processor with a longer instruction pipeline that would reach a higher frequency but would do less per mhz, a arquitecture we know as netburst and is the basis for all the Pentium 4 processors up to the prescott,
the idea was that the increse in working frequency would make up for the for the low efficiency per mhz, and since they were still in the mhz race with AMD, it seemed like the right path to take,
while the tualatins, were only produced in low ammounts and finaly only used for laptops since their high intruction per mhz ment lower operating frequency meaning lower consumption,
the Pentium 3 tualatin lead to the Pentium M Banias which was the first Pentium M, that actually fallowed the AMD doctrine, which was lower mhz, more operations per mhz, better efficiency, since people are stupid and think more mhz = more performance, then intel assumed those processors would not succede on a desktop level,
the original Pentium 3 tualatin was Socket 370, a celeron tualatin running at 1.3ghz (fastest tualatin produced) could basicly bring down a P4 willameth at 1.6-1.8ghz at some cases,
since the first netburst implementations were, misrable....
when the p4 started reaching 2.4ghz-2.8ghz, netburst started to mature and the increse in frequency started making up for the low efficiency, so the pentium tualatin was forgutten, untill the centrino plataform came, which was powered by the socket 479 "Banias" Pentium M, which developed in to the dothan pentium M, which then developed in to the Yonah which was the first dual core Pentium M, and since netbust reached its limits, they couldnt take the clock any higher or make the pipeline longer due to heat dissipation and power consumption issues, they fell back on the Pentium M series to make the Core and Core duo processors, which are the conroes,
they have better intrucction per mhz ratio then the Pentium 4 processors, so they require a lower frecuency to perform on the same level as a netburst based pentium 4, in some cases the differenace in frequency between similar performing processors could be up to 0.8ghz or 1ghz, basicly, if the intel israel labs didnt keep the tualatin project alive to create the pentium M series, then intel would be proper fucked right now,
as for overclocking ability, the lower operating frequency and the lower power consumption gives you more headroom to overclock before you reach the mechanical and thermal limits of the arquitecture, as always, remember that a processor overclocking is limited by the quality of the manufacturing process, the purity of the silicon waffle used and random manufacturing conditions, basicly, a processor from one waffle will overclock differently from another that came from a different waffle becuase of possible chemical composition differenaces in the waffle, atmospheric conditions, some asshole who didnt wash his hands after going to the bathroom and then handling the equipment, what shift worked on the waffle, condition of the labs air filters at the time and other random manufacturing conditions, thats why hardcore overclockers take also in to account processor stepping and series,
as for the extreme edition processors, its basicly a normal processor from the series that tested to be able to sopport a higher frequency, usualy equiped with more cache memory and has an unlocked multiplyer, so they give a bit more of overclocking headroom and give a bit more performance, the price is usualy alot higher, and in most cases, the increse in price dosnt justify the increse in performance,