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)

I always thought you had to have the same size ram in each slot, im not sure but that might be why?

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.

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.

Can you tell us what the rest of your hardware is?

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.

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

-mcg

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.

Happen to be running a pair of 8800gtxs + some other addin cards?

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.

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

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
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

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/archiv [...] emory.aspx

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...)

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?

1st thing I'll do tomorrow morning

I might write down all the settings.. see if anything should be switched on or off

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.

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.

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?