Forgotten memory

  • Thread starter Thread starter Andrew Jarvis
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A

Andrew Jarvis

Dear All,

I have a computer running Windows XP SP2 that was built with 3Gb RAM.

I have now increased the memory to 5Gb. The BIOS reports 5Gb but XP is still
reporting only 3Gb.

Is there something I have to do to get XP to see all the RAM?

Best regards,
Andrew
 
Thank-you for the prompt reply.

This article is probably not relevant as my computer is not running in
Physical Address Extension mode.

It is interesting that the article says that even when not in PAE mode the
system only reports 3.12Gb when it has 4Gb.

I have yet to determine whether the GlobalMemoryStatusEx API function can
see this memory but I'm not optimistic!

I have an application that uses Address Windowing Extensions and it is
reporting "Out of memory" when I try and allocate about 3.7Gb.

Regards,
AJ
 
Andrew Jarvis said:
Thank-you for the prompt reply.

This article is probably not relevant as my computer is not running in
Physical Address Extension mode.

It is interesting that the article says that even when not in PAE mode the
system only reports 3.12Gb when it has 4Gb.

I have yet to determine whether the GlobalMemoryStatusEx API function can
see this memory but I'm not optimistic!

I have an application that uses Address Windowing Extensions and it is
reporting "Out of memory" when I try and allocate about 3.7Gb.

Regards,
AJ
Click to expand...

The absolute maximum RAM that Windows XP can support is 4 gb so if
your application can get up to 3.7 gb that is about as good as it is
going to get.

Good luck

Ron Martell Duncan B.C. Canada
--
Microsoft MVP (1997 - 2006)
On-Line Help Computer Service
http://onlinehelp.bc.ca

"Anyone who thinks that they are too small to make a difference
has never been in bed with a mosquito."
 
Thank-you for the prompt reply.

This article is probably not relevant as my computer is not running in
Physical Address Extension mode.

It is interesting that the article says that even when not in PAE mode the
system only reports 3.12Gb when it has 4Gb.

I have yet to determine whether the GlobalMemoryStatusEx API function can
see this memory but I'm not optimistic!

I have an application that uses Address Windowing Extensions and it is
reporting "Out of memory" when I try and allocate about 3.7Gb.

Regards,
AJ
Click to expand...


I'm not familiar with "Address Windowing Extensions" but I know that
PAE requires address translation hardware on your mobo. IME this was
servers. The application has to make PAE calls and this meant things
like Oracle. You seem to be doing your own programming and can
probably do that.

PAE (Program address extension) is an Intel invention and you can
probably find more info on the intel web site.
 
Ron,

I get an out of memory error when I try to access 3.7Gb. I can successfully
access about 2.5Gb.

The AWE documentation clearly states "allows an application to quickly
manipulate physical memory greater than 4GB". There is no mention of an
absolute 4Gb limit under Windows XP.

http://msdn.microsoft.com/library/d.../memory/base/address_windowing_extensions.asp

The following article mentions "running under Windows 2000 Data Center on a
machine with 64GB of physical memory"!

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnsqldev/html/sqldev_01262004.asp

Surely I do not have to go back to Windows 2000 to get this capability?

AJ
 
My first message said that I had put 5Gb in the computer.

It has a twin Xeon mobo.

Read the messages properly before you reply.

AJ
 
Apologies.

I just found this article
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx which
shows that I need either Windows 2000 Advanced Server or Windows Server
2003, Enterprise Edition.

64-bit Windows here I come!


http://msdn.microsoft.com/library/default.asp?url=/library/en-us/memory/base/add
ress_windowing_extensions.asp http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnsqldev/html/s
qldev_01262004.asp
Click to expand...

You need to note that the 64 bit drivers are not readily available for all
hardware components. Some hardware manufacturers are not provide them also.
 
You need to note that the 64 bit drivers are not readily available for all
hardware components. Some hardware manufacturers are not provide them also.
Click to expand...

As I understand it, you can't buy XP64 off the shelf. You need to buy
it as part of a system.
 
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