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Some time ago, I reinstalled Ubuntu, like I did a lot of time before. Since then, Gnome System Monitor and System Information (and any other graphical tool I tried, for that matter) show only 5,7 GiB of my 8GB RAM installed. I have installed the 64bit version and did never have this problem on a previous install.

I found some questions with similar issues, but none of the answers seem to apply to my case, as this is neither a hardware limitation (as it worked before) nor the wrong system installed.

Can somebody make an educated guess where this could come from? Do I have to have concerns about my hardware? I would like to avoid reinstalling, both because of the inconvenience and because I am curious where this might come from.

I have two modules of RAM installed, both with a capacity of 4GB.

Output of free

free
             Gesamt Belegt Frei Gemeinsam Puffer Cache
Speicher:    6000984    4565864    1435120     628788     141264    1428252
-/+ Puffer/Cache:    2996348    3004636
Auslagerungsdatei:   10485756     121952   10363804

memtest

memtest passes without errors. It reports Memory: 6036M but seems to test the full memory (Testing: 8192M - 8678M).screenshot memtest.

I don't know anything about memetest, so I don't know whether that's normal.

UEFI

My UEFI recognises the full 8GB RAM.

Exepert from /var/log/kern.log: Memory map reported from BIOS during the boot process:

Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] e820: BIOS-provided physical RAM map:
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d7ff] usable
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x000000000009d800-0x000000000009ffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000001fffffff] usable
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000020000000-0x00000000201fffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000020200000-0x0000000040003fff] usable
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000040004000-0x0000000040004fff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000040005000-0x000000005b00efff] usable
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x000000005b00f000-0x00000000dae9efff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000dae9f000-0x00000000daf9efff] ACPI NVS
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000daf9f000-0x00000000daffefff] ACPI data
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000dafff000-0x00000000df9fffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000f8000000-0x00000000fbffffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000fed08000-0x00000000fed08fff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000fed10000-0x00000000fed19fff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed1ffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x00000000ffc00000-0x00000000ffffffff] reserved
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000021e5fffff] usable
Dec 26 23:42:00 josh-ThinkPad-T430 kernel: [    0.000000] BIOS-e820: [mem 0x000000021e600000-0x000000021e7fffff] reserved
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  • what's free say? And BIOS & memtest (from boot menu of iso) reports?
    – Xen2050
    Dec 26, 2014 at 18:09
  • @Xen2050: Updated question to add requested information.
    – Joshua Gleitze
    Dec 26, 2014 at 19:05
  • Take a look at /var/log/kern.log and during system boot there will be a section that details the memory map provided by the bios. It will be a bunch of lines that start with either e820 or efi if you are booting in efi mode. Checking that will confirm, but it looks like you have buggy bios that is under reporting the ram.
    – psusi
    Dec 26, 2014 at 21:30
  • @psusi That sounds promising! I updated the question.
    – Joshua Gleitze
    Dec 26, 2014 at 22:54
  • Yep, there is the problem.. your silly bios has marked the 2 GB Of ram from 1.42 GB to 3.42 GB as reserved.
    – psusi
    Dec 27, 2014 at 2:12

2 Answers 2

Reset to default
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I reinstalled Ubuntu on my machine. In the process, I also reset my UEFI (now using efi and secure boot instead of legacy).

This fixed the problem for me. I cannot be sure what the actual problem was. But:

On my old installation Windows reported less RAM, too. Therefore I guess resetting the UEFI was the solution. It seems to be a bug in the UEFI firmware (nevertheless, updating it did not fix the issue).

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0

Memtest seems to do that, reports what "block size" it's currently testing, even if the installed memory doesn't go that high. But it does appear to report 6036 megs...

And free only sees 6,000,984k, or 6GB too.

If your BIOS also reports only 6GB, then it looks like something's happened to your other 2GB or ram... Maybe it's come loose & re-seating it could help, or maybe it's gone or failed?

After updated info:

UEFI's a whole other can of worms, I'm not sure if it's related but nothing else stands out as different... Maybe take a look through the long answer to this Q " Installing Ubuntu Alongside a Pre-Installed Windows with UEFI " or even Ubuntu's help on UEFI

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1
  • Forgot to state that and updated the question, the BIOS recognises the full RAM.
    – Joshua Gleitze
    Dec 26, 2014 at 19:22

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