Windows XP Professional x64 Only Seeing 3GB RAM?

Windows XP Professional x64 and 4GB RAM?
Alright, So with all the development and what not that I do, I decided
to upgrade my system to 4GB of RAM. Also, due to software
incompatibilities with Vista, I decided the my only real choice was
Windows XP Professional x64 for my OS. I ran through the entire
install, got all my drivers, everything seemed to be going well. I got
my RAM today in the mail, slapped it in, checked the BIOS, and
everything looked good. However, once I got into Windows, it only
shows that I have 3GB available: http://i60.photobucket.com/albums/h33/danodemano/Spec.jpg

I checked with CPUZ to make sure that it was seeing the full 4GB and
it was: http://i60.photobucket.com/albums/h33/danodemano/CPUZ_RAM.jpg

Now correct me if I'm wrong, but I had always thought that XP 64-bit
supported something like 128GB of RAM....so why is my system not
seeing the full 4GB???? Is there some option that I have to enable to
allow Windows to use the full 4GB???

Any help would be appreciated, thanks!!

 

There are two BIOS settings which may need to be made. Memory Hole is one,
and may have both hardware and software versions. There is also MTRR, which
is often not available.

You may need to update your motherboard BIOS to have these settings
available. The best place for advice on the settings is your motherboard
manufacturer's forums.

 

--
I dig working on electrical stuff!

 

On my mobo, you need to get into the bios, enter control+F1, which
adds more features to tweak. Then find "memory remap."

 

Interesting....I will try that and let you know how it turns out. I
have an HP laptop though so I don't know how much I can do with the
BIOS.
This is my motherboard info if that helps:
http://i60.photobucket.com/albums/h33/danodemano/Motherboard.jpg

 

No luck.....I can't seem to get into any of the hidded options of the
BIOS. It's propably something that HP has done to keep me from doing
it, I'm sure.....
Grrr....guess I'm just out of luck at this point, unless someones has
any ideas???

 

What did HP tell you when you asked a support person?

 

They said that it doesn't support 4GB of RAM and that there was
nothing that they could do....the typical BS answer I'm sure.

 

It's not BS. I have a box with a mobo that refuses to support 4GB ram under
Windows x64. It does support 4GB under 32-bit Windows but not 64-bit. It
does happen. It is a design flaw and would take a different mobo to fix.

 

Well I would have though that a motherboard in a system that's hardly
6 months old would support 4GB of RAM....guess that's just to much to
ask though.

 

When a design fails all bets are off. When HP does not offer a configurator
option for 4GB you can bet that something is up. If you use the
configurator for an HP d4996t, for example, you will see a 4GB option. On
other models you won't. That means that HP has been unable to test a system
with 4GB reliably and therefore won't sell it that way (because they cannot
support it).

 

*shrugs* Well either way....I'm still a bit disappointed about only
being able to use 3GB of my RAM. Thanks to everyone that helped, I
really appreciate it!!!!!!

 

Replace your mother board. A good mobo that supports 4GB of ram costs less
then $100. I'm using a low end Asus M2A-VM, and even that el-cheapo board
lets me use all 4GB under XP64.

 

I agree. Replace the mobo (but research thoroughly, especially the forums).

 

I would but I'm guessing that's a bit difficult on a laptop Plus,
until the system is out of warranty, I really don't want to screw with
it....

 

Not always easy to do with an OEM machine, such as those from HP and Dell.
They inevitably have some proprietary, non-standard configuration that makes
it difficult or impossible to put a regular mobo in their system.

 

Ahh, a laptop - that is a different beast entirely! You are pretty much out
of luck....

 

Yeah....that's kinda the way I'm seeing it....unless a future BIOS
update fixes it.

Also, on a totally unrelated note, the newer Dell stuff uses standard
ATX/MicroATX boards so it's super east to swap. I don't know about
the HP desktops.

 

A BIOS update won't fix it. The chipset can only do 32-bit addressing,
so there is no way to not have an overlap when you install 4GB RAM

http://www.intel.com/products/chipsets/945pm/index.htm

 

Oh I didn't realize that that chipset could only support 32-bit
address, that explains a lot. Thanks!!!!