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Can a 32-bit process use more than 3GB of RAM on a 64-bit platform?

Hi

I think the question speaks for itself. Are there things developers can do to have their 32-bit applications utilize more RAM if it is availble on a 64-bit system (Windows) wihtout having to recompile etc. and if so, how? Pointers to technical papers will be much appreciated.

Thanks
Vyyk

Kent Olsen

Hi Vyyk,

A 32-bit application is limited to 3GB (2^32) addresses. That's hard-wired into the definition. A 32-bit Operating System can use more than 3G, but has to play tricks with memory management by using instructions not available to application (user) code.

If the application does a lot of I/O on temporary files you can create a ramdisk so that the I/O is to memory. That will help. It's not really addressing more than 3GB but it is a way to utilize more than 3GB.

The long-term solution is probably to have 32-bit and 64-bit versions with the 32-bit being constrained to the hardware limit of 3GB and the 64-bit free to use the larger memory available to it.

Good Luck,
Kent

Vyyk_Drago

ASKER

Hi Kdo

Thanks for that. I came across this article some time ago http://pcgamingtips.blogspot.com/2010/04/yes-virginia-32-bit-windows-can-use.html

and was just wondering if that also meant that applications written properly to have large address awareness even as 32-bit processes could be coaxed into using the additional memory a 64-bit system might have available.

Thanks again
Vyyk

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Kent Olsen

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