4 GB in laptop but only 3,230.18 MB showing

[jorgen]

No, it's not:

http://msdn2.microsoft.com/en-us/library/aa906211.aspx

"On 32-bit versions of Windows, PAE is disabled by default."

I take note on this, which I think most people use:

"On a computer that supports hardware-enabled Data Execution Prevention
(DEP) and is running a 32-bit version of the Windows operating system
that supports DEP, PAE is automatically enabled when DEP is enabled"

 

[ray]

Is this normal?

Spend five minutes looking through the group - at least the fifth time
this week the same question has been asked.

 

[Ken Blake, MVP]

Is this normal?

Yes.

All 32-bit versions of Windows (Vista as well as XP), even though
they have a 4GB address space, can only use *around* 3.1GB of RAM.
That's because some of that address space is used by hardware and not
available to the operating system and applications. The amount you can
use varies, depending on what hardware you have installed, but is
usually around 3.1GB.

What applications are you running that leads you to think that 4GB
would give you any greater performance than 3GB?

 

[Ken Blake, MVP]

Ok, well that's cool, as long as it is being used..right? I may not see it,
but it's being used I hope.

It is *not* being used.

 

[Blake Mengotto]

May main concern was for running VM's (Virtual PC) on my laptop. I want to
built out one W2K3 DC, one SCOM 07 server (maybe with SQL 2005 all on one
box), and one E2K3 Exchange server.

At most, I would have to have 4 vm's.. One DC, one Exchange, One RMS SCOM
server, and SQL 2005.

I think this is doable, but will be very slow no doubt. Memory allocation
to the VM's is what concerns me most.

 

[Chris Game]

It is *not* being used.

Two posts back in the thread you said that some of this *was* being
used by hardware... You MVPs really ought to catch up on your
product training or at least read up on this stuff so you can
explain it properly. It's all there in the KB or tecknet somewhere!

 

[Dustin Harper]

The RAM is not being used. The 4 GB address space is being used. Only ~3.2
GB of RAM is used in the address space.

If you want the lengthy, technical exlpaination, let me know. I can point
you to a few great sites which go into a lot of detail on it.

 

[Ken Blake, MVP]

Two posts back in the thread you said that some of this *was* being
used by hardware...

No, I didn't.

You MVPs really ought to catch up on your
product training or at least read up on this stuff so you can
explain it properly. It's all there in the KB or tecknet somewhere!

No, *you* need to learn to read more carefully. What I said is that
"some of that address space is used by hardware." If you don't know
the difference between RAM and address space, don't blame me.

 

[Ken Blake, MVP]

May main concern was for running VM's (Virtual PC) on my laptop. I want to
built out one W2K3 DC, one SCOM 07 server (maybe with SQL 2005 all on one
box), and one E2K3 Exchange server.

At most, I would have to have 4 vm's.. One DC, one Exchange, One RMS SCOM
server, and SQL 2005.

I think this is doable, but will be very slow no doubt. Memory allocation
to the VM's is what concerns me most.

Well then you need to either resign yourself to not being able to use
much more than 3GB, or else run 64-bit Vista.

 

[Tim Slattery]

Is this normal?

Yes. See here: http://members.cox.net/slatteryt/RAM.html

 

[Tim Slattery]

So Vista 32 bit will only see 3 GB and be able to use 3 GB? I thought if
you had more memory, even if windows could not use it, other applications
that are memory intensive could..

No. It cannot be accessed at all.

I guess this is wrong and I can only access this memory if I upgrade to the 64bit
version. Is this a correct assumption?

Exactly right.

 

[Tim Slattery]

And PAE is the mode Vista runs in by default.

I don't think so. 32-bit Vista handles at most 4GB, I've never seen
any claim for more than that. If PAE was active, then it would have a
36-bit address space, which would be 68,719,476,736 bytes.

 

[jorgen]

I don't think so. 32-bit Vista handles at most 4GB, I've never seen
any claim for more than that. If PAE was active, then it would have a
36-bit address space, which would be 68,719,476,736 bytes.

If you have a NX-enabled CPU and has DEP configured, then Vista loads
the PAE kernel. But just because the CPU is capable of going beyond 4G,
is not the same as Windows' memory manager will go up there

 

[Sean Wilson]

All 32-bit systems can't ever handle more than 4GB.
4GB 'is' the Max, however, when loaded into Windows it will often report it
as 3.2GB (or lower) because it's unable to use all 4GB.
I myself am not an expert on how it works, but that's generally what it's
about.

 

[jorgen]

All 32-bit systems can't ever handle more than 4GB.
4GB 'is' the Max, however, when loaded into Windows it will often report
it as 3.2GB (or lower) because it's unable to use all 4GB.
I myself am not an expert on how it works, but that's generally what
it's about.

But they can. It is all about making changes to the page table (it's a
part of the x86 architecture). But for various reasons, Microsoft won't
support the physical address space above 4G in Vista and XP.

 

[guitardude]

the math says your missing over 800 mb of ram. as far as being normal, I don't
know. I have noticed that windows sometimes doesn't report the right amount
though. go to http://www.cpuid.com/cpuz.php to download a program called
cpuz. it will tell you a lot about your memory and other things to. It will
tell you your memory manufacturer and how much you have installed. this is
the direct download link: http://www.cpuid.com/download/cpu-z-143.zip just
unzip and run the exe
guitardude