XP Pro doesn't recognize 2gb of ram

[Shaklee3]

Hi, I just built a new uATX computer with the asus a8n-vm csm board. I have 2 gb (4x512) of ocz pc3200 ram. The bios shows 2048MB, but when I go to system properties in windows, it only shows 1.5MB and right below it, it says physical address extension. The weird thing is that if I go into msinfo32, it says total physical memory 2048MB. This is a fresh xp install. What could be the problem?

 

[GregANDTCH]

it says physical address extension.

Mine says that, so I figure that part's normal.
Are you using onboard video?

I've only got 512mb, so I don't have experience with larger amounts.

 

[imported_BikeDude]

Originally posted by: Shaklee3
(4x512) of ocz pc3200 ram. The bios shows 2048MB, but when I go to system properties in windows, it only shows 1.5MB and right below it, it says physical address extension.

First of all, PAE is usually used to extend Windows' address space beyond 4GB. Except... for XP it doesn't. (MS say that many drivers for consumer hardware are sometimes not built to handle 64-bit addresses, so only 2003 uses PAE for this, and up until nVidia's 81.85 driver I thought MS did this only to force people to buy 2003 Server)

Aside from extending the address space (assuming 2003 Server), PAE has another interesting side-effect. Every memory page has a header which the OS uses for housekeeping. This header is bigger in PAE mode thus allowing the OS to tag memory pages as readonly or writable (no space left in the old non-PAE header). This is a requirement for DEP. Presto, XP supports PAE, but not more than 4GB memory. (and you have to deduct some from that, see below)

So, yeah, it'll say PAE. Doesn't really mean anything. Something else is eating half a gig worth of memory.

You wouldn't happen to have a couple of 512MB video cards in there? (PCI/AGP/PCIe devices tend to map into the virtual address space below 4GB, and although 2.5MB eaten by PCI devices would be extreme, I guess it isn't impossible...) You can check this by looking at Device Manager -> View | Resources by connection (look under Memory).

And this being a fresh installation means your boot.ini is pristine, without any bothersome /maxmem switches, right?

If you boot memtest86 -- will it see all the memory?

 

[Shaklee3]

Well this motherboard has onboard geforce 6150 video, and the only option to disable it in the bios that I saw was to set the onchip vga frame buffer from 64mb to disabled, still no luck. There was no option to disable it under onboard devices. I have a radeon x300 in the pci express slot and it works fine. memtest86 shows all 2gb of ram just fine and my boot.ini has no odd switches in it. Here is my boot.ini

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer

I also notice that if I try editing the boot.ini file in msconfig and set the maxmem switch, no matter what I type in there it takes it back down to 1.5gb. Aby ideas?

 

[GregANDTCH]

What does it show under Everest?
Everest Home

 

[Shaklee3]

It shows 1.5gb:

http://img3.imageshack.us/img3/1830/untitled6hv.jpg

 

[imported_BikeDude]

What does dev mgr show? (under View | Resources by conn. -> memory)

 

[Shaklee3]

That doesn't exist...There are a bunch of things but no memory in the place you said.

 

[Slikkster]

What happens if you pull one stick of ram out? What does it show then? This will test to see if you've got something robbing it.

 

[FlyingPenguin]

If you have an onboard Geforce it's almost certainly using party of your memory. It shouldn't be using 512Mb though.

I would be curious what happens if you put only 2 sticks in there (total 1gb). How much RAM does Windows report?

 

[Shaklee3]

Thanks a bunch guys. I removed one, booted it, and it still showed 1.5gb of ram. I took all of it out and reseated it to a different slot and now it shows 2GB. One last question, what is the ideal page file size for this much ram, should I turn it off? Thanks again.

 

[montag451]

If you have 2GB RAM, then it should be safe to limit it at 200 or 300MB. Don't turn it off, cos there are apps that use the pagefile, and it will just confuse them.
Could be worth experimenting as every system is different, and so are the user's needs.

 

[FlyingPenguin]

DO NOT TURN OFF THE PAGE FILE. As montag451 said, there are some apps that will not function properly without it.

I also don't believe in the theory of reducing the pagefile size dramatically if you have lots of RAM. This can also cause problems. Stick to a page file size between 1 and 1.5 times your ram size. Frankly I would recommend you use the Windows default (which is usually 1.5). I would just make the minimum and maximum sizes the same to keep the pagefile from constantly resizing.

If you want to make your pagefile the most efficient, disable it, defrag, then enable it and make it a static size (same min and max numbers). You'll then have one contiguous pagefile.

 

[Slikkster]

I'd say let Windows manage the pagefile. With hard drive sizes the way they are now, it should never be an issue. I've never seen any definitive proof that manually adjusting the pagefile has any performance benefit for today's pc's with copious amounts of ram and disk storage space.

The only time I mess with my pagefile is if I have some kind of non-standard shutdown or lockup where I have to power off the pc without going through the shutdown process.

When that happens, I delete the pagefile in recovery console (you need to copy a file to the name pagefile.sys to do this).

For example, in recovery console, I will type:

copy c:\boot.ini pagefile.sys
del c:\pagefile.sys

(pagefile.sys will not show up in recovery console; hence renaming the file to take it's place).

Then, I'll just exit recovery console and let Windows rebuild the pagefile.sys upon restart.

 

[imported_BikeDude]

Originally posted by: Slikkster
For example, in recovery console, I will type:

copy c:\boot.ini pagefile.sys
del c:\pagefile.sys

What on earth could this possibly solve? You can create a 5GB file filled with the string "fubar", name it pagefile.sys, boot Windows, and it'll be just fine (if not, then it is a bug and should be reported to MS). There's nothing in the old pagefile that is of any use to Windows at the time you next boot.

The only situation I can think of (or speculate) where that could help, is if you have a bad area of your drive or something, and NTFS for some reason is unable to remap that area (currently in use by the pagefile), but I suspect you'll have other more serious problems at this point. Imminent drive failure can often crash Windows. (atleast the last five cases that happened to me seem to indicate this)

I also question the strategy of letting Windows handle the size. I'd rather set a max size that I feel is relevant. If I ever reach that limit, then I know I need to buy more memory or change the software I run. No need to let things grow on their own.

 

[Slikkster]

Not sure I know how to answer that. Suggest you do a little research on the matter. The fact that MS has a support page on how to do just what I posted would suggest a reason for doing so. I have had pc issues in the past where a corrupted pagefile was causing issues, as have others.

Here's the KB page:

http://support.microsoft.com/kb/q255205/