Does more than 4GB of RAM affect the performance of SBS2003?

Hi all,

Does more than 4GB of RAM affect the performance of SBS2003?

We have a 2003 SBS server (32bit) and as I understand this OS does not support more than 4GB of RAM. In this server we have 10GB of RAM. Do the remaining 6GB not effect the performance at all? I was thinking: maybe it still does inprove performance, not so much by the OS perhaps, but maybe the hardware itself CAN make use of it.

Anyone any idea?

2003 DOES recognize 10GB with a third party mem check tool.
AgrippaSenior IT ConsultantAsked:
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Gary CaseConnect With a Mentor RetiredCommented:
The simple answer to your question ["Does more than 4GB of RAM affect the performance of SBS2003?"]  is No, it neither helps nor hinders the performance.

There is, however, one case where it would be helping -- if the installed memory modules are 4GB modules (i.e. if your 10GB is comprised of either 2 x 4GB and 1 x 2GB or of 2 x 4GB and 2 x 1GB), then the memory subsystem is likely running in dual channel mode;  whereas if you removed all but a single 4GB module it would revert to a less efficient single channel operation.    If your installed memory is all 2GB modules, then as long as they're in the correct slots to get dual channel operation, you'll get all the performance you can by just leaving 2 modules (4GB total) installed.

But other than that, the answer is simply No -- there's no benefit from the additional memory.

You are correct that the standard version of Server 2003 R2 x32 (of which SBS is a subset) does not support more than 4GB either.    So unless you move to the full Server 2003 Enterprise version -- which supports up to 64GB with the x32 version) or to a 64-bit OS you can't use the additional memory you have installed.
MacroShadowConnect With a Mentor Commented:
The operating system cannot make use of more ram than it is built to, the fact that third party tools recognize it is due to the fact that physically it's there.

See this.
XaelianConnect With a Mentor Commented:
Sbs 2003 32-bit only supports 3,75GB like all 32-bit systems. You need to look if your processor supports 64-bit. If it does, you can use sbs 2003 R2 which supports 64bit. So you can use your 10GB.

Now you have 6GB in the server who aren't used by the system. A sbs  2003 with same resources as you with only 4GB RAM will have the same performance as your server.

Your 3rd party tool just reads out how much RAM is installed but not how much your server can use.

Hope this helps you.


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Frosty555Connect With a Mentor Commented:
The 4GB limitation is both due to the 32-bit architecture of the OS (which under most circumstances only allows 4GB of allocatable memory), AND due to a limitation intentionally imposed by Microsoft on the SBS 2003 operating system with the intention of limiting it's usefulness in a large enterprise environment.

You would benefit from moving that extra memory to another server that can use it, or upgrading the OS to one that can address the extra memory.

As MacroShadow said, your third party tools can see the memory only because it is physically present in the system. It can be inventoried, but that does not mean that the OS is making any use of it.
Lee W, MVPConnect With a Mentor Technology and Business Process AdvisorCommented:
SBS supports 4 GB of RAM like all 32 bit operating systems.  How much of that is seen depends on the hardware configuration and capabilities (the limit is NOT 3.75 GB). I have a Dell PowerEdge 1900 that makes 3.99 GB available for SBS.
AgrippaSenior IT ConsultantAuthor Commented:
SBS 2003 (even R2) does not support 64 bit, does it?
R2 does support 64bit. But your processor needs to support it. Since sbs 2003 R2, server OS'es support 64-bit architecture. But if you want to use sbs 2003, you need to migrate to it. So best to do for you is placing that 6GB of RAM that is to much in another server who can benefit from it. I wouldn't recommened migrate to sbs 2003 R2 because there aren't much changes becide the 64-bit support added.
Lee W, MVPTechnology and Business Process AdvisorCommented:
> R2 does support 64bit.
This is untrue.

SBS 2003 R2 does NOT support 64 bit.

SERVER 2003 R2 DOES, if you install the 64 bit version.  But SBS 2003 R2 and SERVER 2003 R2 are different products.  Microsoft never updated the 2003 version of SBS to include 64 bit Windows.
Ok yes. I made an error, answered with my mobile. Server 2003 R2 had a 64bit version.
sbs 2003 + sbs 2003 R2 doesn't have a 64-bit version.

But the rest of my answers stay the same :). You won't benefit from it. 32 bit can address 4GB RAM in theory. But in practice it can only use 3.25-3.75 GB RAM. That's stating a fact.
Manpreet SIngh KhatraConnect With a Mentor Solutions Architect, Project LeadCommented:
ElisysAutomatisering: As said its not about the Windows version but 32bit (x86) cannot understand anything more than 4GB so if you have more its only going to adversely affect the performance of the machine and degrade .... so best is to remove the additional .... but if its very IMP and you plan to remove get the best or a ticket with MS to be on the safer side.

- Rancy
AgrippaSenior IT ConsultantAuthor Commented:
Ok, thankx for all responses.<br /><br />I installed 2 x 2GB in dual channel operation. Since there is no SBS 64 bit, this is it. It is running great now.
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