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DL380 G4 with 4 GB RAM, Windows sees only 3.5 GB

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George Av
Occasional Visitor

DL380 G4 with 4 GB RAM, Windows sees only 3.5 GB

Hi, I have a DL 3480 G4 with 4GB RAM, but Windows (2003) reports only 3.5 GB RAM.
The memory distribution is: Socket 1-4 512 MB memory modules; socket 5-6 1024 MB memory modules. On System Management Hompage it shows that total physical memory=4GB; used by OS=4GB. AMP Mode Status: Advanced ECC; Configured AMP Mode=Advanced ECC; so On-line Spare is not configured.

I also have a server with identical configuration, and windows reports corectly 4 GB RAM.


Do you have any advice ?

Thanks,
George
4 REPLIES
ramesh_naik_
Esteemed Contributor
Solution

Re: DL380 G4 with 4 GB RAM, Windows sees only 3.5 GB

Hi George,

To utilize the System memory that is normally reserved for the Intel chipset and other PCI devices accessible to the operating system when exactly 4 GB of memory is installed, updated System ROMs have been released that will remap the 512 MB lost to PCI memory above 4 GB.
Upgrade the System ROM available at:
http://h18023.www1.hp.com/support/files/server/us/download/24639.html


The new System ROM releases will require that PAE mode be enabled with exactly 4 GB of memory installed for certain 32-bit versions of the Microsoft Windows operating systems if the remapped memory above 4 GB is to be used. However, HP recommends that this memory not be used due to the performance loss that occurs when using PAE mode.

PAE is supported on 32-bit versions of Windows, PAE is disabled by default and the /pae boot parameter must be set in the BOOT.INI file to enable PAE.

Hope this works!!!

Regards,
rmn
NMory
Respected Contributor
George Av
Occasional Visitor

Re: DL380 G4 with 4 GB RAM, Windows sees only 3.5 GB

Thanks. I belive that's exactly what I need. I just checked the settings of second server and PAE is enabled.

From what I understood, PAE is a low level remapping of memory which causes some CPU usage. In the advisory regarding it says that:
"In systems with more than 4 GB, the behavior does not occur because the chipset supports remapping the memory lost to PCI devices to a memory region above 4 GB."
I don't really understand this; if there are more than 4GB RAM this means that PAE is enabled (because it wouldn't work any other way) or is it some other magical method to use more than 4GB RAM ? In this way I think I'll preffer a memory upgrade :)

Thanks,
George
ramesh_naik_
Esteemed Contributor

Re: DL380 G4 with 4 GB RAM, Windows sees only 3.5 GB