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View Full Version : Windows XP does not recognise 4GB Ram (shows 3.25GB)



george12
13-05-2007, 09:56 PM
Hi,

I have a PC here with 4GB DDR2-800 Ram in an Intel DQ965GFEKR motherboard that supports up to 4GB of DDR2-800 (what I have). It supports 8GB of DDR2-667 and lower.

Windows XP Pro 32 bit sees 3.25GB, while the Intel Hardware Monitor and BIOS see the full 4GB. I have been Googling around and know that I need to enable/disable some memory options in the BIOS. But there are none!

I think my BIOS needs to be somehow unlocked to enable advanced options but I haven't worked it out yet...... Under chipset options, I have 4 things to play with and they are all basic fool-proof settings.

There's nothing about overclocking, memory options, etc.

Any ideas?

The_End_Of_Reality
13-05-2007, 10:07 PM
XP 32 bit only picks up that much no matter what... if you want the full 4GB, you need a 64bit OS

Just because the mobo supports it DOES NOT mean that the OS supports it

george12
13-05-2007, 10:10 PM
XP 32 bit only picks up that much no matter what... if you want the full 4GB, you need a 64bit OS

Just because the mobo supports it DOES NOT mean that the OS supports it

Thanks for that. Ram is cheap so I'll just leave it there and hope the guy doesn't mind. Computers with 4GB of Ram is a bit of a learning curve for me :p.

The_End_Of_Reality
13-05-2007, 10:14 PM
No problem :)

Well there is that additional 256MB over 3GB if I am not mistaken and plus I doubt that the mobo will run dual channel at all with an uneven number of RAM sticks which means a reduction in performance and by the looks of the amount of RAM, this was built with performance in mind :nerd:

beama
13-05-2007, 10:20 PM
shared video ?

PaulD
13-05-2007, 10:26 PM
MS 32bit server versions cope with much more than 4G

Quote from another forum "The restriction to 3 GB or so in XP is motivated by code in the OS that attempts to work around bugs in the crappy drivers typically associated with consumer hardware.

Server systems are expected to have a more reliable set of drivers."

The_End_Of_Reality
13-05-2007, 10:30 PM
shared video ? That mobo does have intergrated, but the max RAM it can have according to Wikipedia is 256MB, provided it is the GMA 3000 (which I am pretty sure it is) and not the GMA X3000 which is able to use 384MB, but the GMA 3000 still leaves 512MB unaccounted for then... ;)

EDIT: I have just noticed a small flaw in one of my above posts... "you need a 64bit OS" should read "you need XP 64 bit or Vista 64 bit to take full advantage of the full RAM (for desktop OSes)" there, much sounder :p

PaulD
13-05-2007, 10:41 PM
Part of the 4G physical address space is used for PCI stuff so you never get to use it all on a desktop MB chipset.

godfather
13-05-2007, 11:50 PM
And under XP almost nothing in the way of applications can or will use that much RAM anyway.

pctek
14-05-2007, 07:19 AM
Quote from another forum "The restriction to 3 GB or so in XP is motivated by code in the OS that attempts to work around bugs in the crappy drivers typically associated with consumer hardware.

Oooh. A MS fanboy! Blame the hardware people, not the mighty MS.

PaulD
14-05-2007, 08:00 AM
I can link you to the original thread if you're really interested. The comment related to why Server 2003 doesn't have the same restriction. MS don't write the drivers for the hardware.

BIFF
14-05-2007, 08:25 AM
I have had high end Dell workstations shipped to me configured using the
/3GB and /PAE switches in the boot.ini, you may want to investigate this.

george12
14-05-2007, 10:05 AM
I have had high end Dell workstations shipped to me configured using the
/3GB and /PAE switches in the boot.ini, you may want to investigate this.

That's the first thing I checked, PAE is enabled already and there's no 3GB switch - but I see more than 3GB anyway.

PaulD
14-05-2007, 10:11 AM
The /3GB switch applies to the division of virtual memory per process between os and application. Only some apps like Photoshop can use this.

Mike
14-05-2007, 10:26 AM
And under XP almost nothing in the way of applications can or will use that much RAM anyway.Obviously my work application fits under the "almost nothing" banner :)

Mike.

george12
14-05-2007, 11:07 AM
Obviously my work application fits under the "almost nothing" banner :)

Mike.

What's your work application?

This PC is intended for an architect, and I'm sure plenty of Ram will be used. But I don't see a really good workaround. He is using Windows XP instead of Vista for maximum compatibility with his software (3DS Max etc) and afaik there are some things that don't like Windows XP Pro x64 very much (anyone care to tell me if that's right or not?). I will run it past him though.

Mike
14-05-2007, 11:27 AM
What's your work application?

This PC is intended for an architect, and I'm sure plenty of Ram will be used. I use a GIS application called ArcGIS, and also AutoCAD (so similar area to an architect I imagine). We were looking at Windows 2003 to be able to use more than 3GB (and for added stability), but in the end we're going to stick with XP in the short term for maximum app and driver compatibility. Will look at changing OS and adding RAM at a later stage. Am also getting dual-core Xeon and 2 PCI-Express video cards for 3 screens :D (I couldn't work with less than 3 screens now that I've had 3 for a while. Probably couldn't go to more than 3 though due to RSI issues LOL).

Mike.

bill214
15-08-2008, 03:40 PM
I have this exact issue and it's very frustrating because there is a Microsoft article about it and it's incomplete as to whether or not the OS actually uses the memory when it doesn't see it and the mainboard sees all of it.

My mainboard will take up to 8 Gig of memory and I have 4 GB (2 each,2GB strips), all of which is seen by the mainboard and only 3.2 GB of which is seen by the OS (XP Pro service pack 2).

The is a MS article that addresses the issue and says XP will use up to 4 GB of RAM but that you have to add a switch in the boot.ini file.

http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx

I have followed the instructions inserting the "/3GB" switch in various places in the appropriate string (there are a couple of others theres already) and even replacing one of those with the new switch but XP still only sees 3.2 Gig.

I've run across a couple of other people reporting that the switch didn't help them either, including the person that I got the knowledge base link from.

I've also found posts that lead me to believe that the same issue exists in Vista.

Some people say that other resources on the mainboard like video and such may use some of that memory and cause the OS to not report it all but I have to wonder if it's not just a bunch of people that don't really know.

I do know that in previous OS versions on the WIN 95/98 kernel all of the memory was recognised...or at least on all the computers I had ocasion to be that detailed with. I don't remeber using anywhere near tha much memory on those though, and none of the ones I'm running now with 98 SE have over 1 GB.

I suppose it's just the nature of the beast but it would be nice if MS would address this issue fully in the knowlege base and answer questions as to whether or not the unrecognised capacity is being used and why it's not being recognised in the first place.

It makes you feel foolish to have bought a motherboard that will accept 8 gig of RAM, to have bought 4 expecting to upgrade more later and then have it not be recognised. I've also read post suggesting that less memory may run faster.

jwil1
15-08-2008, 04:03 PM
You need to have Windows XP x64 to recognise more than about 3GB.

You must have 32 bit Windows XP - correct???

If the motherboard will support 8GB that does NOT mean you will be able to use all of it - you need a 64 bit OS for your OS to use more than 3GB.

Trev
15-08-2008, 05:07 PM
Did you read this part.
http://www.microsoft.com:80/whdc/system/platform/server/PAE/PAEdrv.mspx
:)

JJJJJ
15-08-2008, 07:36 PM
As I understand it, 32 bit windows will support a total of 3.75 gigsof ram.And that includes video ram.

I have 4 gigs of installed ram and 1 gig on my vid card. Window's recognises 2.75 of available ram. But it acknowledges 4 x 1 gigs installed..

I would love to switch to 64 bit os, but my colour laser printer does not have any available drivers.

PaulD
15-08-2008, 08:56 PM
I would love to switch to 64 bit os, but my colour laser printer does not have any available drivers.

Is it still the HP? You have to keep checking, there was a way of using Canon's drivers for their version of your HP1600 and there's now HP drivers.
http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareIndex.jsp?lang=en&cc=us&prodNameId=1140729&prodTypeId=18972&prodSeriesId=1140734&swLang=8&taskId=135&swEnvOID=2100

JJJJJ
16-08-2008, 10:35 AM
Is it still the HP? You have to keep checking, there was a way of using Canon's drivers for their version of your HP1600 and there's now HP drivers.
http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareIndex.jsp?lang=en&cc=us&prodNameId=1140729&prodTypeId=18972&prodSeriesId=1140734&swLang=8&taskId=135&swEnvOID=2100


The only 64 bit drivers there are for vista

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