Cores versus sockets, what's the performance hit?

[ejward]

Is there a white paper out there that would show the performance hit of going from a 4-CPU 4-socket server to a 4-CPU 2-socket server? All things being equal like CPU speed cache, etc.

I'm having a tough time selling multi-core technology. Everybody wants 4-CPU's in 4-sockets. Guess what? They run on 220volts and we're out of 200volts. I can't imagine that the performance hit is THAT much.

If I went from a single processor box to a dual processor box, I wouldn't expect everything to run 100% faster. For the same token, I woudn't think that taking squeezing 4 CPU's into 2 sockets would give a 100% performance hit.

Maybe there are some areas (CPU intensive applications?) that would actually benifit from having multiple cores on the same chip. I just don't know.

[acr]

Not to sure about the Quad Cores, but i was at a technology show when the Duals were being released and they were quoting a Dual Proc Dual core is approx 1.7 times as fast as its equivalent Single Core..

[ejward]

Yes, I've seen that 1.7 number thrown around before. I just need the paperwork to back that number up. For the cost savings and the power savings, 1.7 is very fair.

[acr]

Single vs Dual..

http://www.barefeats.com/dc20.html

Dual vs Quad..

http://www.barefeats.com/quad02.html

I suppose its always worth remembering, the Quad Core H/D's are no quicker than the Dual or Single core H/D's..

It always depends on what your Apps are doing..

http://www.intel.com/products/processor/Pentium_D/index.htm

Message was edited by:

acr

[oreeh]

The real performance increase depends on the applications.

With normal SPEC benchmarks the increase is between 70% and sometimes 100%. But these benchmarks hove nothing to do with the real world - especially not with virtualization.

acr already mentioned the magic 1.7.

To back it up take a look at the spec site (but see my note above).

[glynnd1]

I asked an AMD rep this recently at a VMUG meeting, and for the coming quad cores he said we could expect a 40% to 50% performance increase.

This Dell whitepaper:

http://www.dell.com/downloads/global/solutions/muirhead_preprint_new.pdf

compares the Intel 5160 (Dual core 3Ghz) with the 5355 (Quad core 2.66Ghz) in the PE2950 and performance gains vary between 47% & 69% depending on the VM.