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Proliant DL580, PAE and missing memory

Paul Murgatroyd_1
Occasional Visitor

Proliant DL580, PAE and missing memory

Hi,

I have had a good read through of many of the articles here on PAE, and none of them are of help. My problem is this. I have 4 ProLiant DL580 G2's with 8GB of RAM each (they all count up and test out perfectly) When I install Windows Server 2003 Enterprise onto them, I have listed 3.5GB in the System Properties. After enabling the /PAE option in boot.ini, the server then shows 7.5GB available (although a total in msinfo32 of 8192MB). Can someone tell me where the other 512MB is hiding? Or what has happened to it? Is this normal behaviour as all four machines are exhibiting this same symptom.

thanks very much

paul
2 REPLIES
Prashant (I am Back)
Honored Contributor

Re: Proliant DL580, PAE and missing memory

Hi Paul,

The maximum amount of physical memory that will be available to the operating system and applications is in part determined by the following criteria:

The number and types of PCI devices installed in the system.
Support for PCI Hot Plug capability. (PCI Hot Plug reserves additional memory to facilitate swapping of devices without bringing the entire system down).
Processor support and server chipset design.
Memory usage based on Hot Plug PCI Reservations can be approximated as follows:

For example, the ProLiant DL580 and ProLiant ML570 have two PCI buses. Each bus has two hot pluggable slots and a virtual slot (three slots total); therefore, there are six slots that reserve Hot Plug PCI resources. For all six empty Hot Plug PCI slots (no PCI devices installed), the cap is the following:

Disabled - 6-slots x 0-MB (reserved memory space) = 0MB
Normal - 6-slots x 40-MB (reserved memory space) = 240MB
Extensive - 6-slots x 144-MB (reserved memory space) = 864 MB

The memory reserved for mapping the PCI devices and used for implementing PCI Hot Plug capability appears to be "lost", since it can not be recognized by the operating system. This memory reservation scheme is mandated by adherence to the PCI specification and the Intel x86 server architecture design, which are industry standards. It is universal for all vendors using Intel x86 architecture and incorporating PCI architecture.


Regards,
Prashant S.
Nothing is impossible
Prashant (I am Back)
Honored Contributor

Re: Proliant DL580, PAE and missing memory

Hi,

Look for Bios try to disable the hot plug option regarding the PCI then check again might help you.

Regards,
Prashant S.
Nothing is impossible