Possibly, a reason, but I think the main reason is to do with scale manufacturing costs and efficiencies. It's fairly common practise to make 1 high spec versi

Possibly, a reason, but I think the main reason is to do with scale manufacturing costs and efficiencies. It's fairly common practise to make 1 high spec version of a chip and then lock parts of it to make the budget versions. For example, the AMD Phenom "Toliman" (X3) and "Kuma" (X2) CPUs are just "Agena" (X4) chips with 1 or 2 cores disabled. (http://en.wikipedia.org/wiki/List_of_AMD_Phenom_microprocessors http://en.wikipedia.org/wiki/List_of_AMD_Phenom_microprocess...) When the X4 chips are manufactured they are tested, and if a core fails any tests it is just locked and sold as an X3/2. This increases manufacturing yields by making use of some of the failures. Of course as there is also higher demand for the lower-middle spec CPUs, sometimes perfectly working chips are restricted to meet the supply requirements for each market space. And of course, often the different clock speeds are really just the same chips with locked multipliers. I believe Sony followed a similar procedure for the PS3 cell CPUs - http://en.wikipedia.org/wiki/Cell_%28microprocessor%29#Commercialization http://en.wikipedia.org/wiki/Cell_%28microprocessor%29#Comme...