I have an application that is running faster On a 1.4ghz (2mb l2
cache) xp pro Centrino Laptop 512 mb ram than a dual processor Dell
Poweredge 2.4 ghz (512kb level 2 cache)windows server 2003 xeon server
(2 GB ram).

The application is mostly a Visual Basic DLL running as MSACCESS.EXE
in Task manager.

The difference in execution time is the Dell server is 20 % slower.

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Request for Question Clarification by webadept-ga on 29 Nov 2004 22:07 PST

Hi, 

My guess would be that your server is running a "server OS" with many
tasks, and your laptop is running XP or something similar, hence it is
only focusing on running the software. Also, many applications are not
written to use dual processors, and the OS has to compensate for this,
which causes the OS to run the software slower as well.

If you could let us know more about the server, such as what services
are running at startup, and more about the laptop, such as the OS it
as, I'm sure that we could give you a much better response.

webadept-ga

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Clarification of Question by philmyers-ga on 29 Nov 2004 22:31 PST

The Laptop is running XP Pro SP2
The server is running Windows Server 2003
The server is running no other applications and all performance
options are set as per a workstation i.e. optimise for programs not
background services.

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Clarification of Question by philmyers-ga on 30 Nov 2004 00:15 PST

Could it be the Level 2 cache ? That appears the only factor in favour
of the Laptop.

The L2 cache difference leaps out at you, but it might be tricky to
prove this is the source of the performance lag.  I'm not sure what
chipsets either system is based on, but an "undocumented" way of
disabling cache for some chipsets is discussed here:

http://www.intel.com/design/support/faq/embed_chipset/430hx.htm

The other possibility that occurs to me is that there may be too much
memory(!) installed on the server box.  At some point memory
performance studies show that applications can suffer with the
installation of excess memory.  This might be an easier test to do
(apart from a risk of triggering MS's registration code by changing
memory configurations).

regards, mathtalk-ga

This page provides a possible answer:
http://www.bestpricecomputers.ltd.uk/ent/dual_processors.htm

"PC suppliers will be happier to charge you extra for a dual processor
computer whether you are going to benefit from it or not. In fact they
may not know that most programs run slightly slower on a dual
processor computer."

What happens is that in a single processor system when the CPU runs of
information to process in it's cache (on CPU memory) it goes to the
main system RAM for more. In a dual processor system the CPU first
looks in the other CPU's cache before going to main memory. If the
program is not optimised for use on dual CPU systems then there will
be no info in the second CPU's cache. Yet, the first CPU will keep
checking there for information. If it does that often enough per
millisecond it can seriously impact on performance. You can test this
by taking one CPU (or disabling it in the BIOS) and seeing if the
performance improves.

Other info on dual Opteron technologies:
http://www.bestpricecomputers.ltd.uk/guides/dual_opteron.htm

And Dual Xeon technologies:
http://www.bestpricecomputers.ltd.uk/guides/dual_xeon.htm