Could someone pls explain Intel stepping to me? Thanks!

[GeoffS]

I'm curious about what the codes mean, and what considerations I need to keep in mind for SMP with each the P3 (both slot and FCPGA), C2, and original Celeron.

I have a pair of retail C400 that have 'For Uniprocessor Systems Only' on the box, yet they run on my BP6 in dual mode with no problems that I can see.

I believe I read somewhere that the original Celeron PPGA can be used for SMP, but that the Slot1 needs mods... true?

Thanks in advance for helping me out!

 

[AndyHui]

A stepping is a minor revision to the processor core that includes bugfixes and or tweaks for improved yield, and sometimes (very rarely) for improved performance. A stepping is indicated by an increment to the last digit of the CPUID:

A CPUID of
0681 is the cA2 stepping of the Coppermine Pentium III
0683 is the cB0 stepping, which had a few bug fixes over the cA2 and had its yields improved, and
0686 is the cC0 stepping, which had its yields further improved over the cB0.

Given the above information, overclockers will generally go for the cC0 stepping, as the improved yields makes a higher probability of getting better speeds.

Coppermine Pentium IIIs with the cB0 stepping or later, are capable of SMP. The cA2 stepping is not capable of SMP.
Celeron IIs (or Celerons in FC-PGA format) are not SMP capable. There was a time when Intel marked PPGA Celeron boxes with "For Uniprocessor systems Only" to discourage their use in SMP, but made no changes to the design; SMP was not disabled for these processors.

 

[Perryg114]

Can someone define the meaning of SMP.

Perry

 

[AndyHui]

SMP = Symmetric Multi-Processing.

In otherwords, more than one processor. Usually it is dual processing, although there are 4-way, 8-way and larger systems as well.

In my post above, I have said that the cA2 stepping of the Coppermine Pentium III is not SMP capable. This means that it cannot be used in dual processor or multiprocessor systems.

 

[GeoffS]

Thanks, AndyHui for taking the time to reply! Have a good one!

 

[Wuming]

hmm... i never knew C2s are not capable to SMP. does that mean if i have 2 C2s on a BP6 i would not be able to get it to run at all? are CuMines SMP enabled?

 

[AndyHui]

Wuming: read my first post carefully. It answers all your questions.