MB does not recognize total memory

[cheartwell]

Ok I have an older Alienware Area-51 with an ASUS P4C800E Deluxe MB. The specs claim it will support 4GB. I replaced my original 2GB (4 512MB DIMMs) with 4GB (4 1GB DIMMs). Only 3GB of the memory is recognized (shows 3GB in both the BIOS startup and in the properties in Windows XP). :(:

 

I HAVE verified that all of the DIMMs are working (doesn't matter what combination of DIMMs and slots I use, only 3GB shows). I also tried filling the 4th slot with one of my original 512MB DIMMs - still only 3GB registers.

 

I'm using 4 Corsair Value Select 1024MB PC3200 DDR 400MHz DIMMs (C13-2920). Is there a compatibility problem that I overlooked or is there some other explanation? I was hoping to double my memory, not just add an extra 1GB. :[pouts:

 

Thanks in advance for assistance.

 

c

[Wired]

Dunno where, but there's a 4 GB memory hole mapping setting somewhere in there (in some BIOSes at least) that'll fix that.

[cheartwell]

Ok, it's just MS doing their best to confound me again. The Windows XP SP2 allows a lot more open addresses for the system to use which eats away quickly at the addresses used for memory. Basically a 32 bit Windows OS cannot address 4GB - how much less than 4GB depends on the configuration to some extent but you will never get the whole 4GB.

 

Time for me to go to 64-bit chip and OS... I wanted to build a new Game machine anyway :laughing:

 

Thanks.

 

c

[Wired]

shows 3GB in both the BIOS startup

 

While what you said is true while within WinXP, Windows can't affect your BIOS.