Ubuntu not displaying full 4GB memory on 64bit installation!

Question

Possible Duplicate:
Why does Ubuntu only show 3GB of RAM?

My Ubuntu install is no using 100% of the memory installed.

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 12.10
Release:        12.10
Codename:       quantal

#sudo lshw -short
H/W path        Device      Class       Description
===================================================
                            system      Computer
/0                          bus         D915GVWB
/0/0                        processor   Intel(R) Pentium(R) 4 CPU 3.60GHz
/0/0/1                      memory      16KiB L1 cache
/0/0/2                      memory      2MiB L2 cache
/0/3                        memory      64KiB BIOS
/0/12                       memory      4GiB System Memory
/0/12/0                     memory      1GiB DIMM DDR Synchronous 400 MHz (2.5 ns)
/0/12/1                     memory      1GiB DIMM DDR Synchronous 400 MHz (2.5 ns)
/0/12/2                     memory      1GiB DIMM DDR Synchronous 400 MHz (2.5 ns)
/0/12/3                     memory      1GiB DIMM DDR Synchronous 400 MHz (2.5 ns)


#cat /proc/meminfo
MemTotal:        3073396 kB

#free -m
             total       used       free     shared    buffers     cached
Mem:          3001        993       2008          0         50        529
-/+ buffers/cache:        413       2588
Swap:         3060          0       3060

Htop displays 3001MB as well.

Then this might not be a duplicate, since you have 64bit installed. — Anwar, Oct 12 '12 at 18:04
It is not a duplicate as in this question, the system used is 64bit and the other topic is about a 32bit system... — vmalep, Feb 04 '18 at 23:57

score 1 · Answer 1 · answered Oct 12 '12 at 19:21

If you are booting using standard BIOS, maybe the BIOS e820 memory map is lying to the kernel. The kernel has to trust what the firmware tells it when it comes to memory layout. To see what you have use:

dmesg | grep e820

alternatively, one can look at the entries in /sys/firmware/memmap, but these are a little tricky to read, so one could use:

sudo apt-get install fwts
sudo fwts memmapdump -

Ubuntu not displaying full 4GB memory on 64bit installation!

1 Answers1