Can someone please tell me the difference between the performance of a QUAD and Dual Processor?

[shajub]

Hi,
I am currently running Scalability tests for a Lotus Domino R5/6 based application.
Ive got some real surprising results... The Dual Processor can Scale much much more than a QUAD Processor.
The details of the processors are as below....

DUAL Processor
Server Make /Model IBM X225
CPU 2 Xeon Processors at 2.8 GHz
Memory 2 GB
Server OS Linux Enterprise 3.0
Domino Version R 6.5.1

QUAD Processor
Server Make /Model IBM xseries 360
CPU X86 - Intel Xeon 1600 Mhz - Quad Processer
Memory 8 GB
Server OS Linux Enterprise 3.0
Domino Version R 6.5.1

Please could someone tell me why Dual Processor is performing better than QUAD Processors?
I would need real valid and convincing answers in case the results are right.
Its real real urgent!!!!

Thanks in advance.

 

[MercenaryForHire]

Definitely wrong forum for one.

My guess is - because the DP system is faster? It's the newer Xeon core, probably HT-enabled. VS the older Northwood-based 1.6GHz and add the overhead of a quad-system, and I could easily see the DP squeaking it out.

- M4H

 

[MemberSince97]

Wow , thanks for the challenge but , I would try the software or Cpu forums... if thats any help.

 

[Appledrop]

because. you are running 2 fast cpus,

and 4 slow cpus.


the MHZ doesnt add up on multi cpu systems - it simply helps multi tasking - if you were running perhaps 4 instances of the tests, the 4x1.6 system may well come out on top.

i hope you get what im saying..

 

[Bateluer]

The Xeons also suffer FSB constraints as you add more CPUs. Assuming you have an 800Mhz FSB on one proc, 2 procs makes an effective 400Mhz FSB, 4 chips makes an effective 200Mhz FSB, 8 chips makes an effective 100Mhz FSB. The Xeons weren't really designed with anything more than Quad operation in mind.

You want an SMP setup, then you should get an Opteron based setup.

 

[shajub]

Sorry Folks its the first time Im posting and guess I messed it...coz this issue has been eating my head.
Thanks a million for such wonderful and fast replies.
It has done me a lot good!!

 

[bunnyfubbles]

Originally posted by: MercenaryForHire
Definitely wrong forum for one.

My guess is - because the DP system is faster? It's the newer Xeon core, probably HT-enabled. VS the older Northwood-based 1.6GHz and add the overhead of a quad-system, and I could easily see the DP squeaking it out.

- M4H

I was under the impression that all P4 Xeons could do HT, even the 1.6s, however 2 x 2.8GHz is probably going to be more efficient than 4 x 1.6GHz as it is true you cannot simply add the CPUs together.