RAM missing for Ubuntu, present for Windows

Question

I am moving a machine from Windows to Ubuntu.

Machine has 4 DDR3 memory sockets, 4 GB each.

After installing Ubuntu desktop 18.04 64 bits, I find only 8 GB, using "free command", but "dmidecode -t 17" command and also "lshw -c memory" command show 16 GB are detected.

I read here it is the BIOS limiting the size

Ubuntu on x64 sees 2G of 12G RAM installed

But I am 99 % sure the 16 GB RAM were used by Windows.

I have been to the BIOS and find nothing related to configuration.

Bios version is 980DE3/U3S3 and here it says it supports up to 32 GB :

https://www.asrock.com/mb/amd/980de3u3s3/

Any ideas on what can I do ? Thanks.

As requested, the data in proper format : (sorry)

PS1.-

nicolau@mars:~/sebas/_local_tinet_files$ sudo lshw -C memory
  *-firmware                
       description: BIOS
       vendor: American Megatrends Inc.
       physical id: 0
       version: P1.00
       date: 02/10/2015
       size: 64KiB
       capacity: 1984KiB
       capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int10video acpi usb ls120boot zipboot biosbootspecification netboot
  *-cache:0
       description: L1 cache
       physical id: 5
       slot: L1-Cache
       size: 288KiB
       capacity: 288KiB
       clock: 1GHz (1.0ns)
       capabilities: pipeline-burst internal write-back unified
       configuration: level=1
  *-cache:1
       description: L2 cache
       physical id: 6
       slot: L2-Cache
       size: 6MiB
       capacity: 6MiB
       clock: 1GHz (1.0ns)
       capabilities: pipeline-burst internal write-back unified
       configuration: level=2
  *-cache:2
       description: L3 cache
       physical id: 7
       slot: L3-Cache
       size: 8MiB
       capacity: 8MiB
       clock: 1GHz (1.0ns)
       capabilities: pipeline-burst internal write-back unified
       configuration: level=3
  *-memory
       description: System Memory
       physical id: 13
       slot: System board or motherboard
       size: 16GiB
     *-bank:0
          description: DIMM Synchronous 1600 MHz (0.6 ns)
          product: 99U5584-005.A00LF
          vendor: Kingston
          physical id: 0
          serial: 53741D0B
          slot: DIMM0
          size: 4GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)
     *-bank:1
          description: DIMM Synchronous 1600 MHz (0.6 ns)
          product: 99U5584-005.A00LF
          vendor: Kingston
          physical id: 1
          serial: 0CF51E12
          slot: DIMM1
          size: 4GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)
     *-bank:2
          description: DIMM Synchronous 1600 MHz (0.6 ns)
          product: 99U5584-005.A00LF
          vendor: Kingston
          physical id: 2
          serial: 3E631E0F
          slot: DIMM2
          size: 4GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)
     *-bank:3
          description: DIMM Synchronous 1600 MHz (0.6 ns)
          product: KHX1600C10D3/8G
          vendor: Kingston
          physical id: 3
          serial: 7D771D73
          slot: DIMM3
          size: 4GiB
          width: 64 bits
          clock: 1600MHz (0.6ns)

PS2.- Ryzen processor - here is the output of provided command :

nicolau@mars:~$ sudo dmidecode -t 4 | grep -i version
    Version: AMD FX(tm)-6300 Six-Core Processor

PS3.- my RAM "99U5584-005.A00LF" is not in the list, all 4 cards are Kingston.

PS4.- memtest says "OK" - found all 4x 4GB memory, identified perfect 2 "models" :

PS5.- BIOS version

nicolau@mars:~$ sudo dmidecode -s bios-version 
P1.00

I know there is a v2 from here

https://www.asrock.com/mb/amd/980de3u3s3/#BIOS

but I am a bit scared to do BIOS upgrade

PS6.- I have removed the "different" RAM and now have 12 GB :

nicolau@mars:~$ free
              total        used        free      shared  buff/cache   available
Mem:       12252164     2002444     9001504      105012     1248216     9872704
Swap:       2097148           0     2097148

Guess this indicates ...

a) I stay with 12 GB with 3 cards

b) I buy 2 identical cards to get up to 16 GB

I am using Ubutnu at home, not too many APPs running simultaneous - guess I will stay with (a)

What is your opinion ?

heynnema · Accepted Answer · 2020-11-06T20:39:39.563

BIOS

ASRock 980DE3/U3S3

User Manual is here.

You have BIOS version P1.00, which is very old.

There's a newer BIOS available, version 2.00, dated 9/23/2015, and can be downloaded here.

Note: Verify that I have the correct web page for your motherboard.

Note: Have good backups before updating the BIOS.

Ryzen/Memory

AMD FX(tm)-6300 Six-Core Processor

Ryzen processors are notorious for memory compatibility issues.

Review the CPU Support List at here and determine your Ryzen model/series product.

Review the Memory Support List at here and determine if your current memory is supported.

Update #1: In reviewing the output of sudo lshw -C memory, we see that your 4 memory DIMMs are not the same. Three are Kingston product "99U5584-005.A00LF", one is Kingston product "KHX1600C10D3/8G". The specs for the "KHX1600C10D3/8G" are different than the other three. That's enough to cause your problem. We'll see what memtest has to say about it.

Update #3:

We pulled out the odd KHX1600C10D3/8G DIMM and now the system properly shows 12G RAM. Will need to purchase a replacement 4G DIMM that matches the remaining three DIMMs.

memtest

Go to https://www.memtest86.com/ and download/run their free memtest to test your memory. Get at least one complete pass of all the 4/4 tests to confirm good memory. This may take many hours to complete.

Update #2:

From the ASRock User Manual, we see how to configure the RAM for dual-channel operation. See below...

RAM missing for Ubuntu, present for Windows

1 Answers1