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Symmetric processing

Ayman Altounji
Valued Contributor

Symmetric processing

I have an 8500 with 4 X 550 2MB processors. Considering the price of getting additional identical processors will the system work with additional 550 1MB processors instead of 550 2MB processors? In other words, can there be a mismatch in cache size in symmetric processing as long as the CUP's are the same speed?

Rick
2 REPLIES
Ayman Altounji
Valued Contributor

Re: Symmetric processing

ProLiant 8-Way Processor Mixing
Compaq has performed extensive testing to verify the rules for mixing processors. Using mixed processors outside the Compaq rules is likely to result in unstable system environments and system failures.

Cannot mix Pentium II Xeon and Pentium III Xeon. Instruction sets are different.
Can mix cache sizes. Each processor pair must be the same cache size or the processor initialization does not complete at the same time, which causes a bus fault.
Can mix speeds.
Faster processors can be used with slower processors, but all must run at the lower speed
The bus/core ratio switches are all OFF, in the default mode
ROM determines the speed of the processors
Do not overclock. L2 cache bus is speed sensitive.
The Compaq processor mixing website is: http://www.compaq.com/products/servers/processor-mixing/
Ayman Altounji
Valued Contributor

Re: Symmetric processing

I am mixing two different 8500's with 2x550 2MB and 6X550 512K and have not
had any problems. Compaq suggests that you install the lowest cache pairs,
in my case the 512s in the first slot pairs. I messed this up at first but it still ran and
seemed ok.