I have a dual boot system running both XP and Ubuntu 64 bit.

I have 8 GB of DDR2 RAM installed.

XP shows 2.75 GB of RAM in System, while Ubuntu shows 7.8 GB.

XP was showing almost 8 GB until just recently.

I tried resetting the BIOS and that did not work.  It was working fine on 
the default BIOS settings recently.

Is there anything within the OS that needs to be tweaked in order for it to 
recognize all the RAM again?

My hardware:

Intel Pentium E5200 Dual Core @ 2.50 GHz
XFX nForce 780i Motherboard
8 GB DDR2 RAM (4 X 2 GB) Dual Channel.
NVIDIA GeForce 9800 GT 1 GB video card.

Thank you

See if your BIOS has a setting to enable Memory Remapping, or some other 
name that sounds like it would be the same thing. Enabling this setting 
tells the bios to remap peripheral ram above the physical ram. Without that 
enabled, peripheral ram defaults to the top of the 4GB range, limiting 
available ram to whatever is left below that. In your case the 1GB video 
ram, plus another .25GB, seems to be sitting right below the 4GB range and 
that's why you're seeing 2.75GB.

"dysonsphere" <dysonsphere@discussions.microsoft.com> wrote in message 
news:E0018B29-90B7-4FD1-BE82-E9B506213EE1@microsoft.com...
>I have a dual boot system running both XP and Ubuntu 64 bit.
>
> I have 8 GB of DDR2 RAM installed.
>
> XP shows 2.75 GB of RAM in System, while Ubuntu shows 7.8 GB.
>
> XP was showing almost 8 GB until just recently.
>
> I tried resetting the BIOS and that did not work.  It was working fine on
> the default BIOS settings recently.
>
> Is there anything within the OS that needs to be tweaked in order for it 
> to
> recognize all the RAM again?
>
> My hardware:
>
> Intel Pentium E5200 Dual Core @ 2.50 GHz
> XFX nForce 780i Motherboard
> 8 GB DDR2 RAM (4 X 2 GB) Dual Channel.
> NVIDIA GeForce 9800 GT 1 GB video card.