Memory >3.5GB not used?

Thomas T. Veldhouse veldy at
Tue Apr 24 19:54:03 UTC 2007

Jonathan Horne wrote:
> i have a system with 4GB memory, doing the same similar behavior.  but, on top
> of not using the last few hundred megs of ram, even the POST shows like 3.6 or
> 3.7GB of ram.  is PAE still a solution for my case?
> [jhorne at canopus ~]$ dmesg | grep memory
> real memory  = 3958833152 (3775 MB)
> avail memory = 3875762176 (3696 MB)

My motherboard has a BIOS option as to how the memory is to be used.  If 
it is remapped, then you can see 3.2GB from a 32-bit OS (like Windows XP 
or Vista x86).  If I turn remapping off, then only 3.0GB will show in 
such a 32-bit OS.  However, a 64-bit OS can see all the memory and use 
it accordingly. 

Check your BIOS.

Tom Veldhouse

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