problem with allocating more than 4GB of RAM to guest OS in workstation 6

[jhbobo]

Hi

I have this problem with allocating more than 4GB of RAM to my guest OS in workstation 6.

I am running workstation 6.0.2, my host is Win2k3 Ent SP2, with 24GB of RAM (Yes, the host can allocate all the physical RAM).

My guest is running Win2k3 STD SP2, and after I installed the guest and allocated 4GB, the guest OS can only read 3.6GB. The strange thing is if I increase the ram allocation to 6GB at the workstation, the guest can now read 4GB. But if I keep increase it up to 8GB, the maximum it will recgonise will be 4 and no more than that.

I understand WinXp has this problem of being able to recgonise more than 4GB of RAM, however, this shouldn't be the case for Win2K3 server.

The VMware documentation suggested version 6 will be able to allocate RAM up to GB.

Can anyone share some light about this?

[asatoran]

Windows Server 2003 Standard 32-bit can only handle 4GB of RAM. You need Win2k3 Enterprise or Data Center or a 64-bit version of Windows to use more than 4GB of RAM.

[jhbobo]

Thanks for the tip. I didn't realise that.

But that still doesn't explain why I have to allocate more RAM than required in workstation to achieve the result for the guest OS to recgonise 4GB of RAM.

Hope someone can answer this part of question.

[asatoran]

It's a quirk with 32-bit Windows. See the links on this thread.

[kristian1978]

Memory hole it's called. Your machine requires the use of some memory for hardware locations, PCI AGP adresses etc. A 32bit as stated will only ref 4GB of which a little is needed by the bios 400Mb by the looks of it (or it's partly number rounding), and 2 for kernel +2 for userland, which can be increased to 3 with the boot.ini switch (PAE remapping).

My 64bit xp guests will happily read upto 8ish... in workstation.

-Kristian