XP Pro SP3 (32Bit) - Upgrade RAM from 2GB to 4GB but shows only 3.00GB

[w3d]

I'm running XP Pro SP3 - 32Bit and have upgraded the RAM from 2GB (4x512MB) to 4GB (4x1GB). I realise the 32Bit OS cannot see the full 4GB, but I was expecting to see nearer 3.5GB (as I have seen reported elsewhere). My System Properties reports just 3.00GB.

When I previously had 2GB installed, the system reported 2.00GB.

The BIOS and the Crucial memory test tool both show 4GB.

I'm thinking I should have saved my money and just bought 2x1GB and kept 2x512MB to make 3GB. But a 4GB upgrade was recommended at the time.

A lot of sites elsewhere suggest that is because of different components in the machine that all take a share of the system RAM. But I don't understand this as when I have less memory in the machine, System Properties shows the full amount of RAM installed.

Do you think this is normal? Where is my RAM?

Thanks.

[DavidGP]

Hi

This is normal occurance and limitation if you are using a 32bit OS over a 64bit OS, the 64bit will see way over 4GB whereas the 32bit struggles and with other factors like GFX card ram does affect what the OS will see so seeing 3GB or 3.5GB depends on these factors.

Depending on your PC hardware spec having 4GB will be good if you plan on migrating to Windows 7 x64 in the future.

[Mimsy]

Yes, it's perfectly normal, as Halo already explained There's a more detailed post on it here (yay, shameless self-promotion!)

[w3d]

Many thanks for your responses and the link you gave was most useful. I found another useful page on why windows doesn't show all 4GB.

I had not appreciated that the dedicated graphics RAM on the gfx card (256MB in my case) would eat in to the system RAM because of the 4GB (32Bit) address limit. I had kinda assumed that the RAM on the gfx card was handled entirely by the processor on the gfx card and would not need to be accessed directly by the main processor - I guess not?!

Anyway, there seems to be a whole chunk of stuff that's allocated a share of the 4GB total:
With 3GB (2x1GB, 2x512MB) RAM installed = 3.00GB reported
With 4GB (4x1GB) RAM installed = 3.00GB reported (NO CHANGE!)

A tad disappointing, may be if I had a 512MB gfx card I could be more appreciative, but there appears to be 768MB of unknowns?!

So, is there currently any advantage for me having 4GB RAM installed over having just 3GB, when 3.00GB is reported in both cases?!

[Mimsy]

Originally Posted by w3d

I had not appreciated that the dedicated graphics RAM on the gfx card (256MB in my case) would eat in to the system RAM because of the 4GB (32Bit) address limit. I had kinda assumed that the RAM on the gfx card was handled entirely by the processor on the gfx card and would not need to be accessed directly by the main processor - I guess not?!

It's not so much accessing it, as it is mapping it into the address space it has for memory. Everything, regardless of if it's in a RAM slot or on your graphics card, or on any other expansion card in there, counts towards the 4GB.

Originally Posted by w3d

So, is there currently any advantage for me having 4GB RAM installed over having just 3GB, when 3.00GB is reported in both cases?!

The way you had it set up, with running dual channel in both cases, not really, no.

[w3d]

Thanks for your reply... I reckon I'll just make sure I have the fastest of the DIMMS in the machine (I have 2x512MB 400MHz, 2x512MB 533MHz and 4x1GB 667MHz - from previous upgrades - I believe the machine has a max of 533MHz anyway) then it looks like I'll have 3GB going spare!

Just a minor query... do you think I'd really notice much of a difference between 400MHz and 533MHz?

[Mimsy]

Originally Posted by w3d

Thanks for your reply... I reckon I'll just make sure I have the fastest of the DIMMS in the machine (I have 2x512MB 400MHz, 2x512MB 533MHz and 4x1GB 667MHz - from previous upgrades - I believe the machine has a max of 533MHz anyway) then it looks like I'll have 3GB going spare!

Just a minor query... do you think I'd really notice much of a difference between 400MHz and 533MHz?

Depending on what you use it for, not really... but don't let that stop you from installing the faster ones!

[rjc862003]

to be honest you don't need more then 2gb when running windows xp

[w3d]

Originally Posted by rjc862003

to be honest you don't need more then 2gb when running windows xp

Well that really depends what you are using your machine for and how many apps you are trying to multi-task. For general web browsing / office work then probably not.

However, I previously had 2GB and found that with several browsers with many tabs open, a code editor and trying to run a graphics app I was maxing out at times. (Some webpages / browser extensions seem to leak memory which doesn't help.) And I'm wanting to run a VM.

[Mimsy]

Originally Posted by rjc862003

to be honest you don't need more then 2gb when running windows xp

That depends entirely on what you want to use it for. I have 2GB on the XP machine I'm currently typing this from, and I could use another GB at least... it would lag less when multi-tasking between game and browser, for example.