Missing Memory?

dmbrown00 · March 4, 2009, 2:48am

I have 4 GiB (2x2) of memory installed. “top” says I have 3287092k (~3.1 GiB) (even as root). Where is the rest of the memory? I am running the 64-bit version of 11.0; so, I shouldn’t have the 3 GiB barrier problem.

ken_yap · March 4, 2009, 3:24am

What’s your motherboard model? Some motherboards cannot physically address memory above 4GB and this ability is needed to access the memory that has been remapped above 4GB to allow certain regions free for PCI, video controllers, etc.

dmbrown00 · March 4, 2009, 3:38am

The board is an ASUS P5N32-SLI SE Deluxe. It has support for 8 GiB of memory. I do have the latest BIOS update.

ken_yap · March 4, 2009, 3:56am

You’d have to look at the e820 lines in the output of dmesg to see how the memory was mapped.

dmesg | grep e820

lwfinger · March 4, 2009, 4:04am

dmbrown00 wrote:
> The board is an ASUS P5N32-SLI SE Deluxe. It has support for 8 GiB of
> memory. I do have the latest BIOS update.

Please post the output of dmesg that starts with “BIOS-provided physical RAM map:”

Larry

caf4926 · March 4, 2009, 5:30am

From a terminal do

uname -a

post here

user · March 4, 2009, 11:17pm

have you reseated the mem?
what was the result of memtest?
swap the ram around…

–
assistant

dmbrown00 · March 5, 2009, 1:19pm

dmesg | grep e820:

 BIOS-e820: 0000000000000000 - 000000000009b000 (usable)
 BIOS-e820: 000000000009b000 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000e9b60 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000cffb0000 (usable)
 BIOS-e820: 00000000cffb0000 - 00000000cffbe000 (ACPI data)
 BIOS-e820: 00000000cffbe000 - 00000000cffe0000 (ACPI NVS)
 BIOS-e820: 00000000cffe0000 - 00000000d0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved)
 BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000000130000000 (usable)
update e820 for mtrr

uname -a:

Linux david-suse 2.6.25.20-0.1-default #1 SMP 2008-12-12 20:30:38 +0100 x86_64 x86_64 x86_64 GNU/Linux

ken_yap · March 5, 2009, 1:27pm

My memory map is very similar to yours. Can you also post more lines below that map? There’s something interesting about the update e820 for mtrr which seems to indicate the map is modified later.

dmbrown00 · March 11, 2009, 6:59am

There is a remap, and it says 768MB of memory will be unusable; I guess I’ll just have to look for a BIOS update.