Can 64-bit guest use the additional memory that can not be used by 32-bit host os?

[czk19790827]

I have a 64-bit CPU and a 32-bit Windows XP installed. And I installed over 4G RAM, only 3.25G can be used by Host. If I install a 64-bit guest in VMware workstation or player, can the guest OS use the additional memory that cannot be used by the host OS?

[AndreTheGiant]

Yes. OS with 64 bit architecture can see (and use) more memory.

Andre

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[admin]

No. Hosted products such as Workstation rely on the host OS (in your case, 32-bit) to manage memory, so you're limited by what the host can handle. Some 32-bit hosts can handle more than 3.25 GB (or whatever, the exact limit varies depending on your setup) RAM due to PAE (e.g. Linux, Server versions of Windows), but it sounds like this is not the case for you. And of course, a 64-bit host would also be able to handle more.

[jagginess]

I'm not too sure about that. but I do know you can run a 64-bit OS on a 32-bit host. Which i currently am doing so with many variants:

64-bit debian on windows 32-bit host.

64-bit windows on windows 32-bit host.

The hardware's processor of course of your host machine has to be 64-bit of course..

i'm using 6.5.x vmwrare..

As for the ram use, it's tricky to say what vmware actually does-- perhaps another forum section someone might now.

There are even ramdisk drivers that can make use of ram locations surpassing the host OS capability..

[Lawrence]

If you have 4GB installed, and the you are only seeing 3.25GB, then you may well be dealing with a chipset/BIOS well-known issue (basically some not so old Chipsets don't support a full 4GB for a similar reason as the the old DOS days of the memory addresses from 640k->1MB). Newer chipsets don't have this issue. If this is indeed your issue, changing your OS won't help