On Thu, 05 Jun 2008 06:37:04 -0400, churin <churin@new.postalias>
wrote:

> Ken Blake, MVP wrote:
> > On Wed, 4 Jun 2008 21:40:57 +0100, "Doug" <Doug
> > <dougti@discussions.microsoft.com> wrote:
> >
> >>> How can I check to see if 4GB is being made available for the system to
> >>> utilize?
> >> It sounds like the RAM isn't being detected. What does the BIOS show?
> >
> >
> >> Either way, the maximum amount of RAM you will be able to access (without
> >> enabling PAE) is 3.2GB.
> >
> >
> > Two points:
> >
> > 1. PAE doesn't help on Windows client operating systems, just on
> > servers.
> >
> > 2. The maximum accessible amount is not precisely 3.2GB, but varies
> > from as little as 2 to 2.5 (in rare cases) to as much as 3.5GB,
> > depending on your hardware configuration. Here's my standard post on
> > this subject:
> >
> > All 32-bit versions of Windows (not just XP) have a 4GB address space.
> > That's the theoretical upper limit beyond which you can not go.
> >
> > But you can't use the entire 4GB of address space. Even though you
> > have a 4GB address space, you can only use *around* 3.1GB of RAM.
> > That's because some of that space is used by hardware and is not
> > available to the operating system and applications. The amount you can
> > use varies, depending on what hardware you have installed, but can
> > range from as little as 2GB to as much as 3.5GB. It's usually around
> > 3.1GB.
> >
> > Note that the hardware is using the address *space*, not the actual
> > RAM itself. The rest of the RAM goes unused because there is no
> > address space to map it too.
> >
> Does the above mean as follows?
>
> BIOS and System|Properties show correct size of installed RAM while
> System Tools|System Information and Task Manager|Performance show the
> maximum usable part of the installed RAM. The maximum usable part could
> be as low as 2GB. Therefor,if 4GB is installed and Task
> Manager|Performance indicates that the Total Physical Memory is 2GB,
> then half of the installed RAM is waisted.



Yes, that's correct. But bear in mind that a usable amount as low as
2GB is very rare. A more typical amount is around 3.1-3.2GB.


--
Ken Blake, Microsoft MVP - Windows Desktop Experience
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