WindowsXP is not recognizing my 4GB of RAM

[mikrev007]

The *problem* is that Microsoft has restricted the total address space to 4GB in xp and vista for compability and other reasons. Other 32bit systems that don't have these concerns have not problem using 4 or more GB - given that the hardware supports it, of course.

 

[RetiredChief]

XP and Vista both will use upto 4 Gigs of ram (2 to the 32nd power).
The problem is that this is the max ram addresses, SO if you have a 512 Meg video card this memory is mapped to the upper portion of the 4 Gigs this would leave about 3.5 Gigs ( there are some other small IO's that are also mapped here.

My system EX Pro System info shows 4 Gigs and 3.5 Gigs avail ( I have a 512 M video card (If you have a 1 Meg video card then this would leave only 3.0 avail)

Now you have to subtract all the programs/applications that are running and what is left is then "Available" for use. Under Windows task manager I show:

Total = 3.406 ( my 512 GPU is subtracted from the 4 .0 Gigs)
Available = 2.6 Gigs (3.4 minus the processes that are running)

Get the general drift

NOTE: In terms of memory, the only advantage on a 64 bit /with 4 gigs RAM is that you do not loose the Space for REmapping Graphics memory. AND you can have more than 4 gigs Ram

 

[strobelp]

From MS 64 Bit website...


Understanding 64-bit PCs
If you're shopping for a new PC you're probably going to come across systems that are designated "64-bit." These are computers running 64-bit editions of Windows Vista, typically with 4GB of memory or more. Compared to 32-bit systems, which top out at around 3GB of memory, 64-bit PCs offer added responsiveness for people who are running a lot of applications at the same time and switching between them frequently.

Pat Strobel

 

[danielpool]

The problem is that this is the max ram addresses, SO if you have a 512 Meg video card this memory is mapped to the upper portion of the 4 Gigs this would leave about 3.5 Gigs ( there are some other small IO's that are also mapped here.

RetiredChief has pretty much posted with what I found when researching this recently. This is a pretty good article which explains what is happening.

Cheers,
~Dan (Not the same Dan as the article author)

 

[terr281]

My Win XP Pro 32 bit machine has 4 GB of system ram installed, and no other PCI cards except video. With that setup:

1. With a single video card with 512 MB of ram, Windows registers 2.75 GB of ram.
2. With 2 256 MB video cards in SLI mode, it registered 2.5 GB of ram.

So, the people that are saying that Windows should be reading closer to 3-3.5 GBs, I don't agree with you.

 

[Braino]

MS explicitly states that Windows XP 32bit is limited to 4GB RAM.

MS also says that the /PAE switch is available on XP, but it is only available to allow Data Execution Prevention, not to increase RAM beyond 4GB.

I have an IBM T60p thinkpad running 32bit XP Pro with 4GB of ram but I only see 3.0GB. So I'm missing 1GB. The concensus I get from several other blogs is the Intel p45 Chipset on this laptop limits what the OS is able to see to 3GB.

Some of my colleagues hae the IBM T61p laptop. It has the intel p65 chipset, and my colleagues say it sees all 4.0GB.

These numbers are despite the fact that both laptops have a 512MB Video card.

I think some chipsets may limit the actual RAM windows sees. Also I hear windows properties sometimes says 4GB when task manager will report 3.5 or less. Physical RAM is not always shared with the video card so don't expect that to always crop your physical ram number.

 

[Guest]

My Comp is having the same issue.. i added 2G and replace a 512bit, so from but when i go to my setup it reads 4.50G and yet my properties shows 3.5 and it use to be 3.24

 

[saran008]

Necropost

 

[The_Prophecy]

This topic has been closed by The_Prophecy