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David
Asked: 2012-05-10 11:13:20 +0800 CST

Ubuntu 12.04 LTS 32bit does not detect 4Gb ram

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I have recently installed 4Gb of ram for an existing 12.04 32bit Ubuntu. It's not being recognised, only 3.2Gb is showing, See:

administrator@Root2:~$ free
             total       used       free     shared    buffers     cached
Mem:       3355256    1251112    2104144          0      48664     391972
-/+ buffers/cache:     810476    2544780

System is PAE capable, See:

administrator@Root2:~$ grep --color=always -i PAE /proc/cpuinfo
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dts
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl est tm2 ssse3 cx16 xtpr pdcm lahf_lm dts

The system us fully patched and tried to run manual PAE upgrade, See:

administrator@Root2:~$ sudo apt-get install linux-generic-pae linux-headers-generic-pae
[sudo] password for administrator: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
linux-generic-pae is already the newest version.
linux-headers-generic-pae is already the newest version.
The following packages were automatically installed and are no longer required:
  language-pack-zh-hans language-pack-kde-en language-pack-kde-zh-hans
  language-pack-kde-en-base kde-l10n-engb kde-l10n-zhcn
  language-pack-zh-hans-base firefox-locale-zh-hans
  language-pack-kde-zh-hans-base
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

I am not sure what else to try to recognise the full physical memory installed other than loading 64bit. Any thoughts? Thanks!

output of uname -r

administrator@Root2:~$ uname -r
3.2.0-24-generic-pae
ram pae 12.04

3 Answers

  1. @fossfreedom - Problem has been fixed by upgrading the BIOS to the most recent one. Thanks for the hint! See available memory output after the change:

    administrator@Root2:~$ free -m
             total       used       free     shared    buffers     cached
Mem:          4026       1105       2921          0         45        311
-/+ buffers/cache:        748       3278
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  2. Even if you were running windows you wouldn't see the entire 4gb of memory allocated. Part of it is reserved for Graphics Ram. If you go to the Manufacturer website and look at the technical specs for your system under memory it will tell you how much of the installed memory is usable.

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  3. 32Bits only goes till 3.2GB of ram. You should upgrade to 64-Bit if you want to take the full advantage of your memory

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