Ubuntu 22.04 amd64 doesn't detect all my RAM

LaurickBo

3/16/24, 7:14 AM

I have one ChannelA-DIMM0 Micron 4 GB RAM Stick on my notebook. The bios and Windows 10 correctly identifies my ram as being 4096 MB, however Ubuntu only detects 3.7 GB. What could possibly be the issue?

free -m

          total        used        free      shared  buff/cache   available


Mem:      3726        1181         453         483        2091        1818

Swap:     3139           0        3139

sudo lshw -c memory

  *-firmware                
   description: BIOS
   vendor: LENOVO
   physical id: 0
   version: KKCN10WW
   date: 04/14/2022
   size: 64KiB
   capacity: 3MiB
   capabilities: pci upgrade shadowing cdboot bootselect edd int9keyboard int14serial int17printer int10video acpi usb zipboot biosbootspecification netboot


*-cache:0
       description: L1 cache
       physical id: 6
       slot: L1 Cache
       size: 128KiB
       capacity: 128KiB
       capabilities: synchronous internal write-back instruction
       configuration: level=1
  *-cache:1
       description: L2 cache
       physical id: 7
       slot: L2 Cache
       size: 4MiB
       capacity: 4MiB
       capabilities: synchronous internal write-back unified
       configuration: level=2
  *-cache
       description: L1 cache
       physical id: 5
       slot: L1 Cache
       size: 96KiB
       capacity: 96KiB
       capabilities: synchronous internal write-back data
       configuration: level=1
  *-memory
       description: System Memory
       physical id: 23
       slot: System board or motherboard
       size: 4GiB
     *-bank
          description: Row of chips DDR4 Synchronous 2400 MHz (0,4 ns)
          vendor: Micron
          physical id: 0
          serial: 00000000
          slot: ChannelA-DIMM0
          size: 4GiB
          width: 8 bits
          clock: 2400MHz (0.4ns)

sudo dmidecode -s bios-version

KKCN10WW

142

0 + 3

laptop

lenovo

ram

22.04

matigo

3/16/24, 7:17 AM

Windows tells you what is installed. `free -m` tells you what can be used. Your notebook is dedicating 256MB of your RAM to the integrated video card, hence the 3.7GB value in `free`. Your `lshw` confirms that the stick is indeed 4GB.

LaurickBo

3/16/24, 7:38 AM

@matigo I haven't even thought that this may be dedicated RAM for something else. Still 0,3 GB seems to be a lot, but well... Thanks for your answer.

paladin

3/16/24, 8:15 AM

@guiverc this is true for ordinary disk drives but not true for memory modules like RAM modules.

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