Windows XP x64 only has 3.5GB Memory

[misternumberone]

My XP Pro x64 machine does not recognize all of the memory. I have 4 gigabytes of memory installed (4*1GB DDR2-667), and it all shows up fine in CPU-Z, but windows only shows 3.5 GB. I am aware of the 32-bit limitations, but this is 64-bit, it should not be a problem.

Does anyone know why this happens?

 

[Boulard83]

ONborad GPU may be using the other 500mb.

 

[misternumberone]

ONborad GPU may be using the other 500mb.

There is no onboard GPU

 

[Boulard83]

The one from your sig ? with a GT540M ? this still can use onboard Ram unless it really have it own ram. Look the Bios.

Aalso disable memory remapping.

 

[neo668]

It's your hardware.

I have an old HP in which I increased RAM from 2GB to 4GB. But no matter what 64-Bit OS I use only 3.19GB will show up.

 

[Operant]

The one from your sig ? with a GT540M ? this still can use onboard Ram unless it really have it own ram. Look the Bios.

Aalso disable memory remapping.

It isn't the one in his sig. The processor and ram are the two most noticeable differences (processor in picture and ram is stated in his post). Different socket types to. As long as it isn't a "G" chipset on the motherboard, then there isn't GPU at fault here.

Anyways, could you tell us what motherboard you are using (the model number is mainly what is needed)?

 

[Boulard83]

It isn't the one in his sig. The processor and ram are the two most noticeable differences (processor in picture and ram is stated in his post). Different socket types to. As long as it isn't a "G" chipset on the motherboard, then there isn't GPU at fault here.

Ho ! I didnt zoomed the pic, i'm at work on a tiny 19inch screen

So yes, listing this laptop hardwae could help us ! And it could still be an onboard GPU pumping the memory. And check remaping in bios.

 

[Operant]

Ho ! I didnt zoomed the pic, i'm at work on a tiny 19inch screen

So yes, listing this laptop hardwae could help us ! And it could still be an onboard GPU pumping the memory. And check remaping in bios.

Assuming that is the correct speed in the picture, its a Pentium D 960 which is a desktop processor

 

[Boulard83]

Assuming that is the correct speed in the picture, its a Pentium D 960 which is a desktop processor

Ya right

 

[ShrimpBrime]

msconfig, boot, advanced options tab. Be sure maximum memory is unchecked or type in the amount you want the OS to boot with usable.

 

[neo668]

Go into your BIOS and have a look at how much memory it says you have. If it still says 3.5GB I'm afraid no matter what you do it will always be 3.5GB. This is a motherboard limitation. And nothing can override the motherboard.

 

[wingman99]

Try memtest86+ and see what it says.

 

[misternumberone]

It's your hardware.

I have an old HP in which I increased RAM from 2GB to 4GB. But no matter what 64-Bit OS I use only 3.19GB will show up.

It showed 4GB on windows 7, but on xp it does not.

The one from your sig ? with a GT540M ? this still can use onboard Ram unless it really have it own ram. Look the Bios.

Aalso disable memory remapping.

No, it is not in my sig, it is a completely different pc. Also, I tried memory remapping just now, it does not change the results whether on or off.

 

[neo668]

It showed 4GB on windows 7, but on xp it does not.

Did you check the BIOS?

 

[misternumberone]

It isn't the one in his sig. The processor and ram are the two most noticeable differences (processor in picture and ram is stated in his post). Different socket types to. As long as it isn't a "G" chipset on the motherboard, then there isn't GPU at fault here.

Anyways, could you tell us what motherboard you are using (the model number is mainly what is needed)?

It is a Dell X8582 with Dimension 9100 BIOS chip, version A03 (latest).

Go into your BIOS and have a look at how much memory it says you have. If it still says 3.5GB I'm afraid no matter what you do it will always be 3.5GB. This is a motherboard limitation. And nothing can override the motherboard.

I must have forgotten to say, this board has before run Windows 7 Ultimate x64 with the same modules and it showed all 4GB.

Try memtest86+ and see what it says.

I did memtest yesterday on a whim and it came out fine with the same thing CPUZ says, all 4GB (it said 4095 megabytes but thats almost the same thing).

msconfig, boot, advanced options tab. Be sure maximum memory is unchecked or type in the amount you want the OS to boot with usable.

Everything there is unchecked.

 

[ATMINSIDE]

I know x64 is supposed to have this done already, but try performing a Physical Address Extension.

 

[misternumberone]

Did you check the BIOS?

Yes, BIOS says it is 4096MB (4GB)

 

[neo668]

It is a Dell X8582 with Dimension 9100 BIOS chip, version A03 (latest).

I've looked up the specs for the Dimension 9100 and it uses an Intel 945P chipset. This chipset supports up to 4 GB memory. This means you are good there.

I'm not too familiar with XP as I have not touched it for years. But my guess is that XP might have some kind of overhead. Or, it might calculate and show memory differently to Win 7.

If you have Win 7 and it can utilize all 4 GB then why not just stick with it? As far as I can see your computer is running normally even though XP might show a smaller memory amount.

 

[misternumberone]

I know x64 is supposed to have this done already, but try performing a Physical Address Extension.

But, isn't that not very good because I can't use all of the RAM at once (say for an application)? or, if I use up most of my normal RAM, and try to run something else that would use all of that remaining, it would not work properly?

I've looked up the specs for the Dimension 9100 and it uses an Intel 945P chipset. This chipset supports up to 4 GB memory. This means you are good there.

I'm not too familiar with XP as I have not touched it for years. But my guess is that XP might have some kind of overhead. Or, it might calculate and show memory differently to Win 7.

If you have Win 7 and it can utilize all 4 GB then why not just stick with it? As far as I can see your computer is running normally even though XP might show a smaller memory amount.

I had to change to winxp because I no longer have a sound card for that PC, and the drivers for the integrated audio are very poorly made and difficult to make work on windows xp, let alone windows 7. That was a big reason, but there were several others also, which are best let alone.

 

[neo668]

I know it sucks losing 0.5 GB for no reason. I have an old HP which I use as a home server. It uses an ATI Radeon Xpress 200 for Intel Processors chipset which supports up to 2 GB memory only. But I stuck 4 GB in and it shows 3.19 GB (even in BIOS). So I guess I'm ahead there.

FWIW, I'm now running Win 8 on it (XP and also Win 7 x64 in a previous life). I don't interact with it much and so everything seems to run perfectly.