Debian does not recognise RAM although BIOS does

System: Debian (stable release from October 2019)
Hardware: J4205-itx => link

I recently installed the system, but it seems Debian is not using the whole RAM. I only installed nextcloud (which comes with an apache server, php atc). Here is some output that might be helpful:

root@debian-simon:/home/simon# free
              total        used        free      shared  buff/cache   available
Mem:        1453848      808424      191980       36952      453444      429164
Swap:       7771128      215552     7555576

root@debian-simon:/home/simon#  sudo dmidecode | sed -n '/^Memory Device$/,/^$/p'
Memory Device
        Array Handle: 0x000E
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: SODIMM
        Set: None
        Locator: ChannelA-DIMM0
        Bank Locator: BANK 0
        Type: DDR3
        Type Detail: Synchronous
        Speed: 1333 MT/s
        Manufacturer: Samsung
        Serial Number: 67422D51
        Asset Tag: 9876543210  [Titel anhand dieser ISBN in Citavi-Projekt übernehmen] 
        Part Number: M471B5273DH0-CH9
        Rank: 2
        Configured Memory Speed: 1333 MT/s
        Minimum Voltage: 1.5 V
        Maximum Voltage: 1.5 V
        Configured Voltage: 1.5 V

Memory Device
        Array Handle: 0x000E
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 2048 MB
        Form Factor: SODIMM
        Set: None
        Locator: ChannelA-DIMM1
        Bank Locator: BANK 1
        Type: DDR3
        Type Detail: Synchronous
        Speed: 1333 MT/s
        Manufacturer: Unde
        Serial Number: 422FD906
        Asset Tag: 9876543210
   [Titel anhand dieser ISBN in Citavi-Projekt übernehmen]        Part Number: RMT3020EF48E8W1333
        Rank: 2
        Configured Memory Speed: 1333 MT/s
        Minimum Voltage: 1.5 V
        Maximum Voltage: 1.5 V
        Configured Voltage: 1.5 V

root@debian-simon:/home/simon# dmesg | grep -i memory
[    0.016839] initial memory mapped: [mem 0x00000000-0  [Titel anhand dieser ISBN in Citavi-Projekt übernehmen] x1cffffff]
[    0.017385] Early memory node ranges
[    0.038097] Reserving Intel graphics memory at [mem 0x60000000-0x7fffffff]
[    0.038453] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.038457] PM: Registered nosave memory: [mem 0x0009b000-0x0009bfff]
[    0.038458] PM: Registered nosave memory: [mem 0x0009c000-0x0009ffff]
[    0.038460] PM: Registered nosave memory: [mem 0x000a0000-0x000dffff]
[    0.038462] PM: Registered nosave memory: [mem 0x000e0000-0x000fffff]
[    0.038465] PM: Registered nosave memory: [mem 0x10000000-0x12150fff]
[    0.098144] Memory: 1421780K/1480704K available (6630K kernel code, 639K rwdata, 2076K rodata, 840K init, 436K bss, 58924K reserved, 0K cma-reserved, 618212K highmem)
[    0.098153] virtual kernel memory layout:
[    0.154868] Freeing SMP alternatives memory: 24K
[    1.436131] Freeing initrd memory: 31204K
[    3.391608] Freeing unused kernel image memory: 840K

So one 4GB stick and one 2GB stick. BITD motherboard required two slots to be populated with LIKE ram sticks. You might check the specs for your hardware. Or at least swap the sticks around so you're using only the 4GB stick, not the 2GB stick.

Originally Posted by Shadow_7 So one 4GB stick and one 2GB stick. BITD motherboard required two slots to be populated with LIKE ram sticks. You might check the specs for your hardware. Or at least swap the sticks around so you're using only the 4GB stick, not the 2GB stick.

Thank you for the answer.

I have to admit I do not know what BITD and LIKE means and could not find anything on google.

Swapping the sticks gives me similiar result for free, so still only 1.4 GB or Ram available. But know the BIOS only shows the 2GB stick.

What happens if you remove the 2GB module?

With dual channel memory both sticks should be the same.

BITD , back in the day ?
i.e. old

LIKE, as is similar
i.e. same configuration

basically they are saying that in the past motherboards needed the memory being used in two slots to be the same configuration
Check the motherboards manual

try with just the 4gb
you should see around 3.5 ( 512mb is being used by the intel gpu )

When I remove the 2GB ram, I get the following outcome:

root@debian-simon:/home/simon# dmesg | grep -i memory
[    0.016770] initial memory mapped: [mem 0x00000000-0x0bffffff]
[    0.017316] Early memory node ranges
[    0.038751] Reserving Intel graphics memory at [mem 0x60000000-0x7fffffff]
[    0.039107] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.039111] PM: Registered nosave memory: [mem 0x0009b000-0x0009bfff]
[    0.039113] PM: Registered nosave memory: [mem 0x0009c000-0x0009ffff]
[    0.039115] PM: Registered nosave memory: [mem 0x000a0000-0x000dffff]
[    0.039116] PM: Registered nosave memory: [mem 0x000e0000-0x000fffff]
[    0.039119] PM: Registered nosave memory: [mem 0x10000000-0x12150fff]
[    0.099247] Memory: 1422044K/1480696K available (6630K kernel code, 639K rwdata, 2076K rodata, 840K init, 436K bss, 58652K reserved, 0K cma-reserved, 618204K highmem)
[    0.099256] virtual kernel memory layout:
[    0.155923] Freeing SMP alternatives memory: 24K
[    1.440753] Freeing initrd memory: 31204K
[    3.392422] Freeing unused kernel image memory: 840K
root@debian-simon:/home/simon# free
              total        used        free      shared  buff/cache   available
Mem:        1454112      744920      237496       78540      471696      454680
Swap:       7771128      294656     7476472
root@debian-simon:/home/simon# ^C
root@debian-simon:/home/simon#  sudo dmidecode | sed -n '/^Memory Device$/,/^$/p'
Memory Device
        Array Handle: 0x000E
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 4096 MB
        Form Factor: SODIMM
        Set: None
        Locator: ChannelA-DIMM0
        Bank Locator: BANK 0
        Type: DDR3
        Type Detail: Synchronous
        Speed: 1333 MT/s
        Manufacturer: Samsung
        Serial Number: 67422D51
        Asset Tag: 9876543210
        Part Number: M471B5273DH0-CH9
        Rank: 2
        Configured Memory Speed: 1333 MT/s
        Minimum Voltage: 1.5 V
        Maximum Voltage: 1.5 V
        Configured Voltage: 1.5 V

Memory Device
        Array Handle: 0x000E
        Error Information Handle: Not Provided
        Total Width: Unknown
        Data Width: Unknown
        Size: No Module Installed
        Form Factor: DIMM
        Set: None
        Locator: ChannelA-DIMM1
        Bank Locator: BANK 1
        Type: Unknown
        Type Detail: None
        Speed: Unknown
        Manufacturer: Not Specified
        Serial Number: Not Specified
        Asset Tag: 9876543210
        Part Number: Not Specified
        Rank: Unknown
        Configured Memory Speed: 1333 MT/s
        Minimum Voltage: Unknown
        Maximum Voltage: Unknown
        Configured Voltage: Unknown

that is odd


the only thing I can think of is mem is being set on kernel command line

cat /proc/cmdline

and check for CMDLINE in
/etc/default/grub

this leads to:

root@debian-simon:/home/simon#  /etc/default/grub
bash: /etc/default/grub: Keine Berechtigung
root@debian-simon:/home/simon#  cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.19.0-6-686 root=UUID=77ac5551-76d8-4ea3-8a87-2a7b0e00dc81 ro quiet
root@debian-simon:/home/simon#

well, the kernel cmdline looks ok ( nothing limiting mem in that )


right now.. I have no idea

can you boot a liveCD/USB ?

if that fails to see full ram, try a CentOS liveCD ( or anything that isn't a Debian derivative )
lets see if it is Debian specific

IME, dual channel and SODIMM have been in practice mutually exclusive technologies. Dual channel is normally used on PC motherboards. SODIMMs are used primarily in laptops. Because laptops do not use dual channel, it isn't necessary to pair matching RAM sticks in them. Sometimes it isn't even possible because there is one stick soldered in place and only one available RAM expansion slot.

This is the first time I've encountered SODIMM on a PC motherboard. I can see only one RAM slot on the board at the URL provided in the OP, so don't understand how dmidecode can be showing more than one memory device.

What I suspect here is either a bad memory controller, or one or more bad SODIMMs, or both, or a memory density on a SODIMM that is not supported by the board - incompatible stick(s?). Does either stick used alone produce an available size equal to its advertised size?

Originally Posted by mrmazda Does either stick used alone produce an available size equal to its advertised size?

No, using 1 stick leads to

simon@debian-simon:~$ head -5 /proc/meminfo
MemTotal:        1454112 kB
MemFree:          238744 kB
MemAvailable:     455552 kB
Buffers:           29420 kB
Cached:           407440 kB
simon@debian-simon:~$ su
Passwort:
root@debian-simon:/home/simon# dmesg | grep -i memory
[    0.016770] initial memory mapped: [mem 0x00000000-0  [Titel anhand dieser ISBN in Citavi-Projekt übernehmen] x0bffffff]
[    0.017316] Early memory node ranges
[    0.038751] Reserving Intel graphics memory at [mem 0x60000000-0x7fffffff]
[    0.039107] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.039111] PM: Registered nosave memory: [mem 0x0009b000-0x0009bfff]
[    0.039113] PM: Registered nosave memory: [mem 0x0009c000-0x0009ffff]
[    0.039115] PM: Registered nosave memory: [mem 0x000a0000-0x000dffff]
[    0.039116] PM: Registered nosave memory: [mem 0x000e0000-0x000fffff]
[    0.039119] PM: Registered nosave memory: [mem 0x10000000-0x12150fff]
[    0.099247] Memory: 1422044K/1480696K available (6630K kernel code, 639K rwdata, 2076K rodata, 840K init, 436K bss, 58652K reserved, 0K cma-reserved, 618204K highmem)
[    0.099256] virtual kernel memory layout:
[    0.155923] Freeing SMP alternatives memory: 24K
[    1.440753] Freeing initrd memory: 31204K
[    3.392422] Freeing unused kernel image memory: 840K
root@debian-simon:/home/simon# free
              total        used        free      shared  buff/cache   available
Mem:        1454112      744920      237496       78540      471696      454680
Swap:       7771128      294656     7476472

I can only surmise the following possible alternatives, alone or in combination:

• SODIMMs incompatible with the motherboard/chipset/BIOS
• defective SODIMMs
• defective BIOS
• defective memory controller

Running memtest86 7 or higher (not to be confused with memtest86+ 5.x) might shed a bit more light on this, but probably not enough to solve the problem. You probably need to contact ASRock support.

Memtest is a good start. Plenty of live media to boot to it.

Wonder if the old deal with video shared memory could be part of it???