Why Won't windows see all 4gb's of memory

I have just built a custom pc with four 1gb sticks. The memory is 6400 ddr2 mushkin, motherboard is an Asus p5nsli, and the cpu is a core2duo intel 6400. The problem i am having is the total amount of memory is not seen by windows xp oem media center edition. It only see's 3.0gb under system in the control panel. However, the bios will see 4098mbs total. I have taken out one of the sticks rebooted and windows still only recognizes 3.0gbs. I have checked the virtual memory and I don't thinks that's the problem. Oh, and I also looked at the motherboard spec's from a 3rd party site and the max capacity is 16gbs. Someone please give me some insight with this issue. Any help would be appreciated.
Thanks

IIRC, you need to do something to the kernel, or the OS itself. MCE was besed off of XP Professional, and needed what was called (I think) the 4 gig switch.

Basically, it was a line of code, or an altered file that tricked the OS into acutally using the extra gig of memory.

EDIT:
it seems this trick was for the 3 gig switch, not 4. More info following. Not sure then how to use the 4 gigs, other than running OSX or linux.

http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx

The only way to get that extra Gig is to use a 64Bit operating system

a 32Bit system isn't capable of addressing that much memory. So you need Windows XP 64Bit edition or any Vista 64Bit edition (or of course any alternative operating system like Linux, etc that also supports 64Bit OS)

jivetrky said:

The only way to get that extra Gig is to use a 64Bit operating system

a 32Bit system isn't capable of addressing that much memory. So you need Windows XP 64Bit edition or any Vista 64Bit edition (or of course any alternative operating system like Linux, etc that also supports 64Bit OS)

Click to expand...

Quote is perfect. I went to Vista website to look into this and it says that Windows Vista 32 supports a max of 4GB of memory. What they don't say is that you can only use 3GB of that because the other 1GB is used for the OS itself. Same thing goes for 64bit operating system that supposed 16GB of memory. I am sure there is some forumula but the true max memory you can use on that OS is probably not 16GB, just like 4GB isn't really the max in a 32bit environment.

If you want to use the 4GB to the fullest, you'll have to get a 64bit capable OS, just thought I would clarify some more that you will find no hack or registry fix or patch or BIOS change that is going to get you the 4GB.

cool thx for the replies, but can you show me link that can verify this problem.

Get Windows XP 64 bit or Vista 64 bit. Don't bother.

this one explains it all:
http://dlsvr01.asus.com/pub/ASUS/mb/4GB_Rev1.pdf

4Gb memory is the theoritical maximum, however you have to take into account Cache and video card memory need adresses, too. Other stuff uses adresses as well, so the max is about 3.2Gb of RAM with any 32bit OS.

64bit bumps it to 256Tb. We're good for another 15 years.

Lets not do this again Read this thread:
http://www.ocforums.com/showthread.php?t=498985&highlight=4gb


We need some kind of sticky for this question, with memory being so cheap these day more people are going to be running 4GB and then wondring why they can't see all their memory on thier 32 bit OS(climbs off soapbox)

mgoode said:

We need some kind of sticky for this question, with memory being so cheap these day more people are going to be running 4GB and then wondring why they can't see all their memory on thier 32 bit OS(climbs off soapbox)

Click to expand...

You are so right

We are working on some info and a white paper for this very reason. It's odd, some people are slamming memory companies, blaming them for the 32bit OS limits

cool guys thx for the help