Windows XP 32 bit Greater than 3.0 GB RAM

[Gerry_Deutsch]

I have a Windows XP Professional 32bit VM running on an ESX V4.1 host.  The VM is running hardware version 7.  I want to allocate more than 3.0 GB of RAM to the VM.  When I allocate 4.0 GB of RAM the guest only sees 3.0 GB of RAM.  Shouldn't the guest see at least ~3.6 GB of RAM?

[a_p_]

You can try to add /PAE in the boot.ini, maybe this helps.

e.g. multi(0)disk(0)rdisk(0)partition(1)\%systemroot%=" Windows XP" /PAE

André

[Gerry_Deutsch]

I tried the /PAE switch it didn't help

[VMmatty]

What about the /3G switch?

[djciaro]

Hi,

Your problem is related to windows and is not unique to Virtual Machines:

you need to modify your boot.ini file in order to use more than 2GB of RAM how it would be recommended to stick to 3GB (3072MB) of RAM as your 32bit OS will not be able to use 4GB.

Have a read of this MS article for more details:

http://support.microsoft.com/kb/291988

regards

Ciarán

[Gerry_Deutsch]

I have tried the /PAE switch and the /3GB switch.  Neither one works.  I  think that there were some changes made with hardware version 7.  I would expect the Windows XP VM to see ~3.6 GB of RAM  Any thoughts on the differences between hardware version 4 and hardware version 7 as it relates to memory?

[djciaro]

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=101329...

A 32bit Non-PAE guest operating system may report incorrect memory size in ESX 4

Symptoms

• 32bit Non-PAE Guest Operating System may report incorrect memory size when using more than 3GB RAM in ESX 4
• 32bit Non-PAE Guest Operating System sees much less memory than the virtual machine is actually assigned when using more than 3GB RAM and using Virtual Hardware version 7

Resolution

This behavior is due to the Virtual Hardware version 7 implementing PCIe which requires a larger Memory Hole for the PCI devices than previous versions.

This behavior is also seen in number of modern chipsets. It is not a virtualization specific issue.

This hole is mapped in between 3 and 4GB, and impact virtual machines with more than 3GB RAM.While this memory allocation is a requirement, it is still possible to have the guest operating use that memory space.To address this, VMware has implemented a memory remapping mechanism, but the guest must be able to address more than 4GB of memory. This is already the case for 64bit operating systems which is why they do not experience this behavior.

Because 32bit operating systems do not address more than 4GB of memory natively, you need to use PAE or BigMem kernels.

[samansalehi]

Fantastic resolution.

Thank u

[satishchirala]

i heard this issue long back ,please check this below link, this shows cpu and ram supports for Operating system recommeded by microsoft.

http://msdn.microsoft.com/en-us/library/aa366778(v=vs.85).aspx