stepping diference

[Machao]

I have a PIII 667, what is the diference betwem cA2, cBO and cCO. Wich one is the best one?

 

[AndyHui]

The cC0 stepping should be the best, or even the cD0 stepping if you can find it (just coming out now).

Gratuitously ripped from pm's posts:

A stepping is a revision of silicon - to be more precise it refers to a change to the mask used to manufacture the chip. This change can for any number of different reasons: to improve bin split (frequency), to fix errata (ie. bugs), to improve yield, to solve an electrical issue and other misc. reasons.

Intel defines steppings in two forms. A letter change is a change to the complete set of masks. A number change only refers to a subset of the masks. So, A1 -> A2 is a change to just a few layers (usually metal), while B0 -> C0 is a change to all layers.

IMO, the most important point to remember about steppings is that you shouldn't mix them in a SMP (multi-processor) system.If you have one 733MHz Pentium III cB0 CPU, and you want to add in another to make a dual-processor setup, then I strongly recommend getting another 733MHz Pentium III cB0, and not putting in a 733MHz Pentium III cA2 or a cC0 instead.

You could think of it as a software release. But it's worth mentioning that rarely steppings are released that may have no notable diffence to the prior stepping as far as the end-user is concerned. A stepping for a yield improvement would not be noticeable at all to the home user. Software releases are almost always released for a reason that would be noticeable to the end-user.

And yes, later should always be better.

 

[techfuzz]

The processor stepping directly correlates to which revision of the chip it is. cA2 was the first revision of the Cu-Mine. As they found errata and problems with the design of the chip they released new steppings/revisions. cB0 was the second, cC0 was the third, and the fourth which currently only applies to 1 GHz+ processors is cD0. There isn't much difference between revisions except if you plan to overclock. Most people believe that the later revisions of chips, cB0 and cC0 will overclock better than early revisions like cA2.

 

[GFORCE100]

The best is the latest usually. CDO has some kind of better heat extraction but I don't know how much of this is true. If you wish to overclock the CCO is the best so far. CBO is good but not as good as CCO. CA2 didn't officially support SMP whereas CBO did. Your best bet is CCO which has a slightly smaller die size of 90mm2 Vs 106mm2.