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I have 3gb RAM, but XP only showing 2Gb?

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April 16, 2007 12:45:03 PM

Hiya,

I have 2x1Gb OCZ platinum PC6400 modules and 2x512 modules of the same spec running in dual channel mode in my P5B Deluxe Wifi board with an e6600.... Windows though is only reporting 2gigs of ram, but cpu-z is saying 3gigs is installed (which is correct, I do have 3gigs), is this normal or is something going wrong? (Shown in the screenshot)

More about : 3gb ram showing 2gb

April 16, 2007 4:17:02 PM

I always thought you had to have the same size ram in each slot, im not sure but that might be why?
April 16, 2007 4:24:57 PM

Your running Windows 32bit, 32bit operating systems only use up to 2 GB of ram, you need a 64bit OS to use anymore then 2GB of RAM
Related resources
April 16, 2007 4:42:11 PM

Quote:
Your running Windows 32bit, 32bit operating systems only use up to 2 GB of ram, you need a 64bit OS to use anymore then 2GB of RAM


Wrong. 4 GB of addressable memory space, which realistically means a 3.2 GB or so limit.
April 16, 2007 4:51:00 PM

Interesting. I have 2x1gb and 2x512 and it properly shows up as 3gb. I'd start by looking up your mobo and seeing if it has any restrictions on mixing ram sizes, and make sure your motherboard drivers/bios are up to date while you're there.
April 16, 2007 4:51:56 PM

Can you tell us what the rest of your hardware is?
April 16, 2007 4:58:55 PM

Quote:
Interesting. I have 2x1gb and 2x512 and it properly shows up as 3gb. I'd start by looking up your mobo and seeing if it has any restrictions on mixing ram sizes, and make sure your motherboard drivers/bios are up to date while you're there.



There hasn't been restrictions on mix/match ram sizes in 10 years for standard chipsets.

What does your bios report? Should show the same as cpuZ.
April 16, 2007 5:00:07 PM

Quote:
Your running Windows 32bit, 32bit operating systems only use up to 2 GB of ram, you need a 64bit OS to use anymore then 2GB of RAM


Wrong. 4 GB of addressable memory space, which realistically means a 3.2 GB or so limit.
THANK YOU!! You save me from having to say it :wink:

-mcg
April 16, 2007 5:39:03 PM

Quote:
3.2 GB or so limit.

Actually i think it's 3.75 without pae on. With pae, 4GB on 32bit.
There seems to be a limitation with pae on 32bit windowsXP and server 2003 std. On enterprise 32bit, if pae's enabled, it supports up to 64; or rather slightly less than that i'd say. :lol: 
April 16, 2007 7:13:29 PM

Happen to be running a pair of 8800gtxs + some other addin cards?
April 16, 2007 8:52:50 PM

Quote:
3.2 GB or so limit.

Actually i think it's 3.75 without pae on. With pae, 4GB on 32bit....:
Nope, 4GB is the total number of *addresses* available with or without PAE on XP Home, Pro and 32-bit Vista.
April 17, 2007 8:14:26 AM

Thanks for all the replies, but I spent most of last night fixing it, by doing a reinstall, windows i think was pretty screwed so i popped vista 32bit on there, and everything is fine once again... What I reckon has happened is after so many dodgy overclocks, and a faulty usb device too, windows crashed so often that the OS probably became corrupted (it was having trouble starting up all together actually, with about 1 in every 10 not requiring a reboot half way through the boot up process)... but now it's all good :) 
April 25, 2007 12:58:15 AM

I realise this is a late post but I have a similar problem and was wondering if anyone could help me out.

I built my own PC about a month ago and everything is running great :D 
Only I have a couple problems.

I have installed 4 x 1GB RAM sticks and XP is only picking up 2.5GB. If I upload system specs to someone like X-Fire or Steam it says I only have 2.5GB as well

Seeing the first post, I download CPU-Z and tested my own Rig. Sure enough, it told me what I had installed was actually there.



If it helps I also have;
2x 640MB 8800GTS' in SLI
Intel Core 2 Duo E6700 @ 2.66 Ghz
nForce 680i SLI SPP Motherboard
RAM type is DDR2

Is there a reg hack or something so WinXP Pro 32bit will actually say I have 4GB (and use it) or is something actually wrong?

Any help will be much thankful
April 25, 2007 3:02:39 AM

No hack, but nothing is wrong; 32-bit Win XP and 32-bit Vista are limited to 4GB of memory addresses, and some of those get used up by system hardware. Whatever addresses are left over (typically 3-3.5GB, but sometimes less, as with your dual graphics cards) are available to be assigned to your physical RAM. The rest of your physical RAM without addresses is unavailable for use by the OS, which is why the OS doesn't report it.
If you want to make use of all your physical RAM, go with 64-bit Vista, Linux, or some other OS.
Here's a decent article: http://blogs.msdn.com/dcook/archive/2007/03/25/who-ate-...
April 25, 2007 3:33:33 PM

So its my GFX cards using up my RAM?

I guess thats why in my BIOS it says "No SLI Memory Detected"

Any chance you'd know how to make it detect it? (The RAM was SLI ready, and i thought the GFX card memory would be the SLI bit...)
April 25, 2007 9:22:52 PM

The more cards (of any type) you have plugged in, the more address space will get taken up. Unfortunately, once you cross a certain threshold (which having two graphics cards will cross), an extra 512MB (IIRC) of address space also gets used up, because of the way the add-on hardware address region was designed initially years ago.

As for the SLI memory, you need an SLI-memory compatible MB (not to be confused with SLI-graphics). I'm guessing your MB is compatible, so I'm not sure why your SLI memory is not being recognized as such -- have you taken a look in the BIOS for any "enable SLI memory" or similar setting?
April 26, 2007 3:14:02 AM

1st thing I'll do tomorrow morning :D 

I might write down all the settings.. see if anything should be switched on or off
January 25, 2008 9:20:53 PM

:cry: 
I have a similar problem, I recently bought 2x1 Gb in addition of my 2x512 Mb but Windows XP only see 2Gb of Ram, I run CPU-Z and it shows me 3Gb in dual channel, anyone has idea what is happening? my 4 sticks are PC3200 Bus400.
March 12, 2008 7:03:46 PM

I too am having the same problem with Windows XP Pro SP2 only recognizing 2.0gb of the 3gb I have installed. My BIOS recognizes the 3 GB, and CPUZ recognizes it as well, but the windows "System Properties" only says 2. I have read a little about adding the /3GB switch, and the /PAE switch in the boot.ini file, but am uncertain as to what one would work, or if it even matters. Any suggestions on how to get Win. XP to recognize the 3gb of ram installed. I have 2x512mb, and 2x1gb, all running in dual channel.
March 12, 2008 8:21:19 PM

davezNot_here said:
I too am having the same problem with Windows XP Pro SP2 only recognizing 2.0gb of the 3gb I have installed. My BIOS recognizes the 3 GB, and CPUZ recognizes it as well, but the windows "System Properties" only says 2. I have read a little about adding the /3GB switch, and the /PAE switch in the boot.ini file, but am uncertain as to what one would work, or if it even matters. Any suggestions on how to get Win. XP to recognize the 3gb of ram installed. I have 2x512mb, and 2x1gb, all running in dual channel.


None of that will help you.

The /3GB switch is for allowing certain apps to utilize 3 GB of RAM maximum instead of just 2 GB. This is good for SQL, Exchange, Photoshop, and AutoCAD.

Honestly, I'm not sure exactly how the /PAE switch works, but I think it has absolutely zero effect in XP and Vista, while in Server 2003, it's automatically enabled without actually using it.

Are you running an ass-load of PCI/PCI-e expansion cards?

You may also want to go into your BIOS and check for the memory remapping option. It needs to be on for 64-bit OSes to use more than 4 GB of RAM. If it's on in a 32-bit OS, then it will cap the OS at 2 GB.
March 12, 2008 8:26:35 PM

i've got one card in the PCI-E slot ( XFX 8800GS). And my BIOS says that there is 3gigs present. So basically, Windows XP (32) will only recognize up to 2, and everyday apps. and gaming will only use 2 gigs anyway?
And if there is a "memory remapping option", does it need to be turned off in 32-bit OS to exceed the 2GB cap?
March 12, 2008 10:10:42 PM

MooseMuffin said:
Interesting. I have 2x1gb and 2x512 and it properly shows up as 3gb. I'd start by looking up your mobo and seeing if it has any restrictions on mixing ram sizes, and make sure your motherboard drivers/bios are up to date while you're there.



Yeah, me too. Maybe it has something to do with your mobo. Maybe it only supports 2 gigs!
March 12, 2008 10:46:14 PM

Thats the risk you take when you mix and match ram, and its not suggested to do so, by microsoft, and by most mobo vendors. You take your chances when you choose to do so. Does it suck? of course, can you fix it? dunno.
March 12, 2008 10:46:50 PM

SumNubX said:
Your running Windows 32bit, 32bit operating systems only use up to 2 GB of ram, you need a 64bit OS to use anymore then 2GB of RAM


Well I know what he was smoking when he wrote this... :whistle: 
March 12, 2008 11:30:16 PM

My mobo is an Asus P5WD2, and it supports up to 8 gigs; and the BIOS recognizes that there is 3 gigs, however Windows XP Pro (32) does not, it says only 2gigs in the system properties. CPUZ says it too. I have 2x512 and 2x1gb in dual channel, all Patriot ddr2-800.
March 22, 2008 8:18:52 PM

^ im thinking of geting another 2GB myslefe...even though only 3GB will be recognized/used...sicne i have already 2x1GB...but lately games take mroe than 2bg for me(about 2,260mb's)...with same mobo P5W DH Deluxe
March 23, 2008 7:21:56 PM

davezNot_here said:
My mobo is an Asus P5WD2, and it supports up to 8 gigs; and the BIOS recognizes that there is 3 gigs, however Windows XP Pro (32) does not, it says only 2gigs in the system properties. CPUZ says it too. I have 2x512 and 2x1gb in dual channel, all Patriot ddr2-800.


ok too many ppl in here smoking crack or something, I have used both winxp, and vista 32-bit and have maxed it out with three 1Gb sticks, and I don't know whats all this fuss...All 3 sitcks show up, I don't like to fill up all the slots though, b/c sometimes some of the pc's i've worked with act funny when u max out the slots, so i never try to unless its necessary for some server or heavy memory user....

even when i max them out I've never had that kind of issue, at least not with 32 bit...
March 24, 2008 12:17:56 AM

Well a good majority of people here are running 4 sticks, and besides having to worry about voltages, there also trying mix 1 gig sticks and 512 sticks.
March 24, 2008 5:12:47 PM

blacksci said:
Well a good majority of people here are running 4 sticks, and besides having to worry about voltages, there also trying mix 1 gig sticks and 512 sticks.


I know silly, silly fools. :lol:  :lol:  :lol: 
March 31, 2008 2:36:34 AM

blacksci said:
Well a good majority of people here are running 4 sticks, and besides having to worry about voltages, there also trying mix 1 gig sticks and 512 sticks.




So then if you are running 4 sticks all in dual channel, they should all be either 512mb or 1gb? And not 2x512mb and 2x1gb?
March 31, 2008 3:58:13 AM

davezNot_here said:
So then if you are running 4 sticks all in dual channel, they should all be either 512mb or 1gb? And not 2x512mb and 2x1gb?
No that's BS. They only need to be the same in the same bank, and that's only with the older MCHs and/or non Intel. Desktop Boards - Single / Dual / Flex memory modes
March 31, 2008 4:21:24 AM

2x 640MB 8800GTS' in SLI = 1280MB of addressable memory gone.

4000-1280 = ~2.7GB's left for ram, so if you are have 3GBs of ram, not all of the ram will be used.
March 31, 2008 7:54:03 PM

Zorg said:
No that's BS. They only need to be the same in the same bank, and that's only with the older MCHs and/or non Intel. Desktop Boards - Single / Dual / Flex memory modes



That's what I had thought; so I wonder why my 2x512mb 1x2gb all running in dual channel only shows 2gb in XP 32?
March 31, 2008 8:28:25 PM

u know 2GB of good memory in dual channel really is more than enough for what most people do in WIN XP [well 32-bit] anyways....
a b } Memory
March 31, 2008 8:32:56 PM

Listen to Zorg, He is correct.
The_Monkey_Man is correct, On 4gig's. When 3 gigs are used the MIMO's are not loaded into Ram, However a small chunk is used for DOS enviorment.

Very good explanation.
www.dansdata.com/askdan00015.htm
April 2, 2008 5:03:17 PM

The_Monkey_Man said:
2x 640MB 8800GTS' in SLI = 1280MB of addressable memory gone.

4000-1280 = ~2.7GB's left for ram, so if you are have 3GBs of ram, not all of the ram will be used.


That can't be because I have Vista with 4GB of RAM and a 8800GT with 512MB. Vista sees 3.5, but its apparent that the system would crash if the rest was just reserved for the video memory. Funny to mention here that most people always say 3Gb or 3.2GB at most, not sure what makes this so special but Vista really does see 3.5GB
a b } Memory
April 2, 2008 6:20:26 PM

ExtremeGimp said:
So its my GFX cards using up my RAM?

I guess thats why in my BIOS it says "No SLI Memory Detected"

Any chance you'd know how to make it detect it? (The RAM was SLI ready, and i thought the GFX card memory would be the SLI bit...)


"SLI MEMORY" is just a confusing branding for what memory manufacturers call "EPP" for enhanced performanc profiles. These are nothing more than extended SPD values that allow your system to configure a memory overclock for you. Advanced users would do better to manually set their memory overclock.
a b } Memory
April 2, 2008 6:22:53 PM

The_Monkey_Man said:
2x 640MB 8800GTS' in SLI = 1280MB of addressable memory gone.

4000-1280 = ~2.7GB's left for ram, so if you are have 3GBs of ram, not all of the ram will be used.


No, 2x 640MB = 640MB, at least in SLI mode. the memory map is the same between the two cards.
April 3, 2008 8:29:27 AM

Zorg said:
No that's BS. They only need to be the same in the same bank, and that's only with the older MCHs and/or non Intel. Desktop Boards - Single / Dual / Flex memory modes


When i did my investigating into this with windows and mobo manufacturers they recommend running sticks with the same amount of ram, and the same manufacturer. Not trying to start a argument here, but I have seen lately more people trying to max out at 3 gigs with a 2x512 + 2x1gig have issues with either the os not recognizing the ram, or the computer not starting at all. Sure intel says its ok, but they dont make the os, so check and see what your os vendor has to say and then follow it, you might not end up like all the folks in here and actually get your ram recognized.
April 3, 2008 10:33:24 AM

If the mobo sees it and it is not unstable then the OS should see it, assuming compliance with the ~3G limit explained in this link. I have seen a lot of problems with people using four identical sticks of 1G each, so the problems that you see with instability or no boot could be the mobo not accepting four sticks properly.

Maybe you could link me to anything that MS has to say on the subject.
December 3, 2008 6:19:43 AM

Hi there, I just saw something very similar. I have a K8N DL motherboard (ASUS). I had 4Gb of RAM installed (winXP was showing 3.2 GB when I clicked on My computer, properties...). I installed a new video card today (the GeForce 9800 GX2). I noticed the system performance drop because paging was happening. I then noticed that Windows showed only 2GB of memory (same process, My Computer, Properties...)

Can someone please enlighten me?

Thanks in advance.
January 27, 2009 3:27:50 AM

I'm having the same problem... Just got some new upgrades to my comp and after formatting I realized Windows XP Pro SP3 is only showing 2GB of my 3GB installed...

I have a eVGA x58 motherboard, 3x1GB Kingston RAM running tripple channel, an Intel i7 2.66ghz, and a Nvidia 8800GT 512mb.

Heres some screenshots of what windows and CPU-Z and the program that came with my motherboard are showing.






Windows and the motherboard program show only 2GB while CPU-Z shows the full 3GB... I downloaded another program that shows RAM usage and that only showed 2GB also...

Is my computer actually using all 3GB or just 2GB like Windows shows?
If you think it is using the full 3GB, is there a way I can be 100% sure?
January 27, 2009 3:38:34 AM

so, i finally discovered that XP takes your new vid card's memory and allocates that amount from your RAM to it. so if you have 3Gigs of RAM, and have a gig vid card, then 3 minus 1 = 2 left over.

solution = vista 64 bit where the vid card does not require the parallel allocation. sorry, frustrating i know, but i ended up going back to my old vid card, rather than "upgrade" to vista.
January 27, 2009 11:36:15 AM

natasha69 said:
so, i finally discovered that XP takes your new vid card's memory and allocates that amount from your RAM to it. so if you have 3Gigs of RAM, and have a gig vid card, then 3 minus 1 = 2 left over.

solution = vista 64 bit where the vid card does not require the parallel allocation. sorry, frustrating i know, but i ended up going back to my old vid card, rather than "upgrade" to vista.


Wrong. 32-bit OS's can only hold 2^32 (4GB) of memory addresses at any point in time. Basic mobo functions usually take up 256MB, leaving you with a max of 3.75GB. A 512MB GFX card leaves you with the famous 3.2GB left over.

64-Bit OS's behave the same way, only they have more space (2^64) than a 32-bt OS. Vista 64 still requires parallel allocation (as you call it), as the GFX card RAM still needs to be addressed by the OS. You simply have a few hundred thousand gigabytes to play with instead of just 4.
a b } Memory
January 27, 2009 12:52:20 PM

In a computer all bytes in the memory system need a unique name. This is called an address. For example, if you have 2 GB of main memory, then there are 2147483648 bytes of RAM in your machine, each of which require an address for the operating system to communicate to it. To give these all an address you need 31 bits to do it. Now, if/when you have 32 bits, you can name 4 GB (2 bytes to the 32nd power = 4GB).

This is why the total addressable space available in a 32 bit OS is 4GB – the OS runs out of addresses and cannot communicate/locate any more bytes of memory because of that.

You may think ”Hey, 4GB of address space… 4GB of RAM… What’s the problem” The problem is that memory isn’t the only thing needing an address. If you install a total of 4GB worth of RAM, the system will detect/use/display less than 4GB of total memory because of address space allocation for other critical functions, such as:

- System BIOS (including motherboard, add-on cards, etc..)
- Motherboards resources
- Memory mapped I/O
- Configuration for AGP/PCI-Ex/PCI
- Other memory allocations for PCI devices

Different onboard devices and different add-on cards (devices) will result of different total memory size. e.g. more PCI cards installed will require more memory resources, resulting of less memory free for other uses.

This limitation applies to most chipsets & Windows XP/Vista 32-bit version operating systems. Again, this is a limitation of the Operating System not having enough address space to allocate to the system *and* the RAM. Not allocating address space to devices renders them inoperable. Not allocating addresses to RAM simply results in the unaddressed section not being used in an otherwise fully functional computer. Therefore the OS designers assign RAM last.

We can have long debates about mathematical fundamentals and discussions about why the original Windows designers couldn't allocate the full theoretical max of 36 bits of address space so that users today would be able to use more resource. But at the end of the day, the designers and engineers 'Didn't Then'. So we 'Can't Now'.


If you install a Windows operating system, and if more than 3GB memory is required for your system, then the below conditions must be met:

1. A memory controller which supports memory swap functionality is used. The latest chipsets like Intel 975X, 955X, Nvidia NF4 SLI Intel Edition, Nvidia NF4 SLI X16, AMD K8 and newer architectures can support the memory swap function.

2. Installation of Windows XP Pro X64 Ed. (64-bit), Windows Vista 64, or other OS which can provide more than 4GB worth of address space.



Note: According to the latest Change Log published by Microsoft, Windows Vista 32bit SP1 will display the installed amount of RAM. This is a display change only.

January 30, 2009 9:54:03 PM

ok... the address space =/= memory I understand

However I have 3Gb physical memory installed, Bios reports 3Gb, CPU-Z reports 3Gb, Crucial Memory Scanner reports 3Gb (and offered a nice price on upgrading to 4Gb). However Windows XP Media Center Edition v2002 SP3 resolutely claims I have 2Gb of memory....

I can't possibly be using 2Gb of address space for video/bios, so where is my 1Gb????
January 30, 2009 11:12:29 PM

If you have between 2 and 3 GB usable RAM then a combination of 32bit xp/vista and memory remapping activated in bios can do that.
January 31, 2009 12:59:26 PM

after much random poking at the BIOS I found that enabling software memory remapping around hardware hole (whatever that is) gives me 2.98Gb... good enough, although still miffed that that other halfs computer has always reported 3Gb (same setup, diff manufacturer, diff motherboard).

Motherboard is ASUS A8N-VM... a lot of google searching shows this is a common issue with this motherboard.
April 19, 2009 9:59:04 AM

ok for anyone still having trouble try disabling your intagrated vidcard it freed the rest of my ram and now i have a solid 3gigs
April 19, 2009 12:21:18 PM

Why does 32-bit show only 3.2 GB? Isn't it expected to support 4GB? And is there some way to disable the graphics card's shared memory?
!