[SOLVED] fresh Arch install fails to recognize all RAM

minteaseu · 2022-11-02 05:59:07

I have been battling this issue for a while now, searching the internet for a cause or fix and so far I've not come up upon something that has helped. I left the issue alone, and have recently installed Arch from a live USB for, mostly the hell of it.

In any case, the BIOS info reports 32GB total memory (4x8GB) while Arch reports 16GB available.

Some stats:
Motherboard - ASRock B450M/ac
Processor - AMD Ryzen 5 2600
RAM - 4x 8GB Teamgroup-UD4-3200 (running @2933)

I've run memtest86 before to the result that none of my ram sticks are faulty. I can run it again on request and provide further output of the results if requested.

Kernel isn't outdated to my knowledge, but I have not tried using any other kernel so far.

Linux arch-homeserver 6.0.6-arch1-1 #1 SMP PREEMPT_DYNAMIC Sat, 29 Oct 2022 14:08:39 +0000 x86_64 GNU/Linux

dmidecode returns 4x8GB as expected:

# dmidecode -t memory | grep Size
        Size: 8 GB
        Size: 8 GB
        Size: 8 GB
        Size: 8 GB

meminfo, however does not:

# grep MemTotal /proc/meminfo
MemTotal:       16308496 kB

I'm aware that the BIOS reporting detection of 4 ram sticks does not mean it can address it properly, and I'm also aware it can be a bootloader issue, though I would need some guidance into actually checking those specifically.
I use GRUB currently, and as for boot entries:

vmlinuz-linux root=UUID=8e805f12-f8b2-47e4-a1cf-963497602fc1 rw rootfstype=btrfs loglevel=3 quiet

Any help is appreciated, and any more info is absolutely accessible upon request. I haven't the slightest clue what could be the issue.

Last edited by minteaseu (2022-12-07 08:57:44)

seth · 2022-11-02 07:44:58

dmesg will show whether and how much RAM gets reserved by what or GART/GTT, but 16GB seems a lot.
memtest86 did detect and test all 4 modules?

minteaseu · 2022-12-06 03:57:30

Actually, something interesting has happened since my last run of memtest86. I've just finished running another test after the system has laid dormant for a few weeks.

memtest86, in the ram list section, detects all 4 physical ram slots as being filled with, as expected, teamgroup-ud4-3200 modules.

Apart from this, though, the test itself when run only addresses 16GB of that ram, effectively half of what it physically detected.

seth · 2022-12-06 07:49:48

Pretty much like dmidecode.

seth wrote:

dmesg will show whether and how much RAM gets reserved by what or GART/GTT, but 16GB seems a lot.

Also maybe look out for BIOS/EFI updates.

minteaseu · 2022-12-07 03:35:54

Ah -- apologies, I hadn't read that first prompt correctly.
I've just now run dmesg at system boot, right after logging in. Here's the log. (0x0.st)

On another note, I did find the BIOS to be heavily outdated, latest being 3.1 and what I was previously running on being 1.5. Successfully updated, yet I see the issue persists. BIOS, as expected still reports the full 32GB; nothing on that end has changed.

seth · 2022-12-07 07:56:13

[    0.000000] BIOS-provided physical RAM map:
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009ffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000000a0000-0x00000000000fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x0000000009bfefff] usable
[    0.000000] BIOS-e820: [mem 0x0000000009bff000-0x0000000009ffffff] reserved
[    0.000000] BIOS-e820: [mem 0x000000000a000000-0x000000000a1fffff] usable
[    0.000000] BIOS-e820: [mem 0x000000000a200000-0x000000000a20afff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x000000000a20b000-0x000000000affffff] usable
[    0.000000] BIOS-e820: [mem 0x000000000b000000-0x000000000b01ffff] reserved
[    0.000000] BIOS-e820: [mem 0x000000000b020000-0x00000000bb69cfff] usable
[    0.000000] BIOS-e820: [mem 0x00000000bb69d000-0x00000000bcdd6fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000bcdd7000-0x00000000bce0afff] ACPI data
[    0.000000] BIOS-e820: [mem 0x00000000bce0b000-0x00000000bd4befff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x00000000bd4bf000-0x00000000bdf77fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000bdf78000-0x00000000bdffefff] type 20
[    0.000000] BIOS-e820: [mem 0x00000000bdfff000-0x00000000beffffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000bf000000-0x00000000bfffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000f0000000-0x00000000f7ffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fd100000-0x00000000fd1fffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fea00000-0x00000000fea0ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000feb80000-0x00000000fec01fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fec10000-0x00000000fec10fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fec30000-0x00000000fec30fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed00000-0x00000000fed00fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed40000-0x00000000fed44fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed80000-0x00000000fed8ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fedc2000-0x00000000fedcffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fedd4000-0x00000000fedd5fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000043f37ffff] usable
[    0.000000] BIOS-e820: [mem 0x000000043f380000-0x000000043fffffff] reserved

% echo $((0x000000043fffffff/1073741824.0))
16.99

[    0.100636] Memory: 16217748K/16700996K available (16391K kernel code, 2092K rwdata, 11380K rodata, 2128K init, 3472K bss, 482988K reserved, 0K cma-reserved)

The BIOS doesn't report more than 16GB

According to https://www.asrock.com/mb/AMD/B450Mac/#Specification the timings matter, though. What if you reduce them to the most coservative values?

d.ALT · 2022-12-07 08:12:48

Indeed... As seth suggested, please check Memory QVL (Pinnacle Ridge) and

minteaseu · 2022-12-07 08:56:08

d.ALT wrote:

Indeed... As seth suggested, please check Memory QVL (Pinnacle Ridge) and

seth wrote:

What if you reduce them to the most coservative values?

This did it, setting ram frequency to the lowest listed on that list for Pinnacle Ridge, 2133, and adjusting timings accordingly results in all 32GB of ram being reported inside of Arch

$ grep MemTotal /proc/meminfo
MemTotal       32793376 kB

I hadn't bothered checking this before, but 2/4 of the modules of ram are technically unsupported by this motherboard, with the other two being supported. This, along with the configuration I had them in would definitely do the BIOS in as is made clear though the support chart.
I suppose to get them running at higher frequencies, a more recent motherboard is required; but for all intensive purposes I am completely fine with the lowered frequency as this system isn't going to be doing much heavy lifting. I will test more configurations to see the maximum speeds I can reach with these modules, but the base issue is resolved.

Thank you seth, d.ALT, for your help and for pointing out what I believe is in major part to me not doing thorough enough research. Cheers!

Arch Linux

#1 2022-11-02 05:59:07

[SOLVED] fresh Arch install fails to recognize all RAM

#2 2022-11-02 07:44:58

Re: [SOLVED] fresh Arch install fails to recognize all RAM

#3 2022-12-06 03:57:30

Re: [SOLVED] fresh Arch install fails to recognize all RAM

#4 2022-12-06 07:49:48

Re: [SOLVED] fresh Arch install fails to recognize all RAM

#5 2022-12-07 03:35:54

Re: [SOLVED] fresh Arch install fails to recognize all RAM

#6 2022-12-07 07:56:13

Re: [SOLVED] fresh Arch install fails to recognize all RAM

#7 2022-12-07 08:12:48

Re: [SOLVED] fresh Arch install fails to recognize all RAM

#8 2022-12-07 08:56:08

Re: [SOLVED] fresh Arch install fails to recognize all RAM

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