4GB RAM reported as 2GB in XP SP2 (32bit)

[DaveB]

Do you suppose that anyone anywhere actually understands how all this crap really works these days?

I'm convinced that it's all an illusion.

It's those little grey barstewards again.

Even back in the days of DOS, Windows 3.1 and autoexec.bat files memory management was a black art. Trying to figure the best sequence to load all your drivers etc into 640k base memory could keep you occupied for hours if you only had a kilobyte or so left to play with.

[Lobby Lud]

PC problem

Run Fdisk

delete partition.

Install Linux

Problem solved

[DimPrawn]

Okay.

[1117]

I've basically made an account just to clarify some issues with windows xp and the whole 4gb ram thing. First of all, Windows XP Home, I believe, has a 2GB RAM limit, whereas Windows XP Pro has a 4GB RAM limit (not 100% sure). Anyway, take a look at this article which explains things in a much better way than I ever could. I doubt I'll ever log back in to this site, but in pure boredom I stumbled upon this thread and felt compelled to help out some... (shrugs) must be because it's Christmas...

http://www.brianmadden.com/content/content.asp?ID=69

Also, 32 bit Windows has the 4GB limit divided between Application and OS 2/2 or 3/1.
64 bit Windows can handle 4GB per process.

Here is a rundown on physical memory support.
Windows XP Home & Pro -- 4GB
Windows XP Pro x64 Editions -- 16GB
Windows Server 2003 Web & SBS -- 2GB
Windows Server 2003 Standard -- 4GB
Windows Server 2003 Enterprise -- 8GB
Windows Server 2003 Enterprise on X86 -- 64GB
Windows Server 2003 Enterprise on x64 -- 128GB
Windows Server 2003 Enterprise on Itanium -- 1024GB

EDIT: Hahaha! Under my nick it says "not worth listening to" because of the number of posts I've made... riiiiiiiiiiiiiiiiiight. Don't listen to me.

[DimPrawn]

What's really strange (and make me think my problem is a hardware one) is this.

My PC has four memory slots.

I have 4 x 1GB DDR 400 RAM sticks.

Put in two and I get 2GB reported in XP Pro SP2 (runs in dual channel mode)
Put in three and I get 2.85GB reported in XP Pro SP2 (runs in single channel mode)
Put in four and I get 2GB reported in XP Pro SP2 (runs in dual channel mode)

WTF!!!

Bios correctly reports 2GB, 3GB, 4GB. It's only Windows that loses the 2GB...

I originally intended the PC to run multiple instances of Virtual PC, but since I can't get the full 4 GB ram required, I'm tempted to switch to XP 64bit and run the applications natively instead.

What a nightmare this has been.

Linux, you ain't so bad.

[TGAOTU]

Linux is bad, m'kay?

TGAOTU - In "Blatant SP" mode!

[NoddY]

http://www.freebsd.org
http://www.openbsd.org
http://www.netbsd.org

You know it makes sense.

[qsrk]

What's really strange (and make me think my problem is a hardware one) is this.

My PC has four memory slots.

I have 4 x 1GB DDR 400 RAM sticks.

Put in two and I get 2GB reported in XP Pro SP2 (runs in dual channel mode)
Put in three and I get 2.85GB reported in XP Pro SP2 (runs in single channel mode)
Put in four and I get 2GB reported in XP Pro SP2 (runs in dual channel mode)

WTF!!!

Bios correctly reports 2GB, 3GB, 4GB. It's only Windows that loses the 2GB...

I originally intended the PC to run multiple instances of Virtual PC, but since I can't get the full 4 GB ram required, I'm tempted to switch to XP 64bit and run the applications natively instead.

What a nightmare this has been.

Linux, you ain't so bad.

But if most system monitoring software running in Windows sees 4GB, and Windows only sees 2GB, wouldn't that mean it is a problem with Windows?

[1117]

Dimprawn, try the following and see what happens:

Right click on My Computer, select Properties. Notice how much RAM is listed. Now, I want you to go to the Advanced tab. Under Performance, click on Settings. On the tabs that appear, click on the Advanced tab. At the bottom you will see a section called Virtual Memory. Click on Change and make sure Custom Size is selected, lower this to like 64MB on both the Initial AND Maximum size (I'd put both at 128MB to play it safe, just in case, you never know). The reason for this is that STATIC sizes are always better than variable ones. In fact, I advise anyone, regardless of how much physical ram they have, to set both initial and maximum to the same size (the bottom of the window lets you know the minimum recommended as well as the highest). The reason for this is that Windows DRASTICALLY slows down when it has to resize the paging file.

Anyway, back to Dimprawn... after you've made the changes Windows will ask you to reboot. Do as told and, after having restarted, right click on My Computer, select Properties, and notice how much RAM is listed NOW. See anything near 4GB?

If you do, the reason for this (it is NO miracle) is that, like I said a couple of posts back (hopefully you read the article), Windows XP has a 4GB memory limit. This memory limit includes BOTH physical memory AND virtual memory. When we got rid of the virtual memory, Windows "sees" your other 2GB (well, almost all two, I think) because there aren't 2GB used in virtual memory, so, since the max is 4GB, it sees all your physical RAM now. I've never tried this, just assuming because, well, it just makes SENSE to me it would do that.

Now, you might say, well! Why don't I just select NO PAGING FILE instead of putting down a static size of 128MB? Well, although it IS doable, i wouldn't recommend it because Windows will act funny when it encounters an error. I' forgot exactly what the problem is, something with memory file dump or something.... argh! Can't remember... either way, just don't do it. However, I hope the above suggestions help you better understand the limits of Windows XP as an OS.

EDIT: Your BIOS will always see the correct amount of RAM because, well, it has no limitations in this aspect, other than the max amount the mobo (motherboard) can hold. It has nothing to do with Windows. It is NOT a hardware problem if your BIOS sees all your RAM, it is a LIMITATION of Windows being a 32-bit OS (any 32-bit OS should give the same problem).

[qsrk]

I think you always need some virtual memory since Windows or some programs are written to access a page file no matter what your settings are.