Arch Linux

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

[SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

Hello,

I have 24GB RAM installed on my PC, 2 x 4GB and 2 x 8 GB, both are dual channel memory stick pairs.

When I check the system info on Arch Linux, I see that only 3.8 GB is recognized from Arch Linux as shown below:

https://i.imgur.com/imDJFVP.png

Operating System: Arch Linux
KDE Plasma Version: 5.25.2
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.5
Kernel Version: 5.18.9-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 8 × AMD FX(tm)-8350 Eight-Core Processor
Memory: 3.8 GiB of RAM
Graphics Processor: llvmpipe

When I enter:

 free -h 

I get:

               total        used        free      shared  buff/cache   available
Mem:           3.8Gi       1.1Gi       1.6Gi       204Mi       1.1Gi       2.2Gi
Swap:          511Mi          0B       511Mi

When I enter:

 sudo lshw -short | grep 'System\ Memory' 

I get:

 /0/26                       memory         24GiB System Memory 

When I enter:

 cat /proc/meminfo 

I get:

MemTotal:        3964540 kB
MemFree:         1552872 kB
MemAvailable:    2249260 kB
Buffers:          157420 kB
Cached:           793696 kB
SwapCached:            0 kB
Active:           399688 kB
Inactive:        1531592 kB
Active(anon):       4064 kB
Inactive(anon):  1194988 kB
Active(file):     395624 kB
Inactive(file):   336604 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:        524284 kB
SwapFree:         524284 kB
Dirty:                24 kB
Writeback:             0 kB
AnonPages:        972072 kB
Mapped:           400024 kB
Shmem:            218872 kB
KReclaimable:     257240 kB
Slab:             334368 kB
SReclaimable:     257240 kB
SUnreclaim:        77128 kB
KernelStack:        7264 kB
PageTables:        13460 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     2506552 kB
Committed_AS:    3216124 kB
VmallocTotal:   34359738367 kB
VmallocUsed:       38092 kB
VmallocChunk:          0 kB
Percpu:             6848 kB
HardwareCorrupted:     0 kB
AnonHugePages:    665600 kB
ShmemHugePages:        0 kB
ShmemPmdMapped:        0 kB
FileHugePages:     98304 kB
FilePmdMapped:     79872 kB
CmaTotal:              0 kB
CmaFree:               0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:               0 kB
DirectMap4k:      256404 kB
DirectMap2M:     3885056 kB
DirectMap1G:           0 kB

So this is weird, seems like there is 24GB RAM installed as shown by lshw but Arch Linux is not properly recognizing it.

What could be the issue?

Thanks.

moderator edit -- replaced oversized image with link.
Pasting pictures and code

Last edited by rajhlinux (2022-07-11 07:06:54)

loqs

Member

Registered: 2014-03-06

Posts: 18,387

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

Please post the full output of the following

# dmesg
cat /proc/meminfo

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

Please post the full output of the following

# dmesg
cat /proc/meminfo

Hello, thanks for quick reply. I have updated my post.

loqs

Member

Registered: 2014-03-06

Posts: 18,387

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

You forgot the dmesg output.

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

You forgot the dmesg output.

I have updated the post again with the "dmesg" output.

Thanks.

loqs

Member

Registered: 2014-03-06

Posts: 18,387

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

[    0.004226] e820: update [mem 0xbf800000-0xffffffff] usable ==> reserved

Reserves everything above 3,212,836,864

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

[    0.004226] e820: update [mem 0xbf800000-0xffffffff] usable ==> reserved

Reserves everything above 3,212,836,864

So the remaining memory space but 3.2GB, is all reserved?

If so, what is causing 20.8GB of Physical RAM space to be reserved, is it not normal?

seth

Member

Registered: 2012-09-03

Posts: 62,183

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

No. You reserve ~400 MB, what's ok (0xffffffff == 4,294,967,295)

[    0.090215] Memory: 3745512K/4141072K available (14343K kernel code, 2099K rwdata, 11004K rodata, 1860K init, 3356K bss, 395300K reserved, 0K cma-reserved)

sudo dmidecode

---

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rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

No. You reserve ~400 MB, what's ok (0xffffffff == 4,294,967,295)

[    0.090215] Memory: 3745512K/4141072K available (14343K kernel code, 2099K rwdata, 11004K rodata, 1860K init, 3356K bss, 395300K reserved, 0K cma-reserved)

sudo dmidecode

Thanks for the reply, so how can I make Arch Linux to use 24GB of ram? FFMPEG and applications are eating up all of the 3.8GB RAM.

Last edited by rajhlinux (2022-07-11 07:08:29)

loqs

Member

Registered: 2014-03-06

Posts: 18,387

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

If you remove the two 4GB modules leaving the two 8GB modules in is 16GB detected?  If not if you remove one of the 8GB modules leaving only one slot populated is 8GB detected?

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

If you remove the two 4GB modules leaving the two 8GB modules in is 16GB detected?  If not if you remove one of the 8GB modules leaving only one slot populated is 8GB detected?

I will try this.

Thanks.

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

I took out the 4 GB RAM pair modules.

The PC was not booting so I had to clear the BIOS CMOS which made the PC boot and used the default BIOS settings.

Arch Linux seems to recognize 16GB RAM:

Operating System: Arch Linux
KDE Plasma Version: 5.25.2
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.5
Kernel Version: 5.18.9-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 8 × AMD FX(tm)-8350 Eight-Core Processor
Memory: 15.6 GiB of RAM
Graphics Processor: AMD Radeon Pro WX 2100
Manufacturer: MSI
Product Name: MS-7693
System Version: 3.0

-----------------------

Leaving one 4GB RAM module along with the 8GB pair, into the PC gives this:

Operating System: Arch Linux
KDE Plasma Version: 5.25.2
KDE Frameworks Version: 5.95.0
Qt Version: 5.15.5
Kernel Version: 5.18.9-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 8 × AMD FX(tm)-8350 Eight-Core Processor
Memory: 7.7 GiB of RAM
Graphics Processor: llvmpipe

Thanks.

Last edited by rajhlinux (2022-07-11 07:09:14)

rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

Alright, I was able to fix the issue, Arch Linux now shows 24GB RAM:

Operating System: Arch Linux
KDE Plasma Version: 5.25.2
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5
Kernel Version: 5.18.10-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 8 × AMD FX(tm)-8350 Eight-Core Processor
Memory: 23.4 GiB of RAM
Graphics Processor: AMD Radeon Pro WX 2100
Manufacturer: MSI
Product Name: MS-7693
System Version: 3.0

It seems like I had to mess around with the BIOS "Over Clocking" settings and enable "AMD XMP(Extreme Memory Profile)".
After that Arch Linux started to show 24GB RAM.

I suspected what caused the issue was the fact that I am using two pairs of dual channel ram sticks, where each pair dual channel ram sticks are from a different manufacturer. This somehow confused Arch Linux and for some reason enabling AMD XMP from BIOS does the trick since it allows to use different RAM manufacturer installed to the motherboard.

Thanks.

Last edited by rajhlinux (2022-07-11 07:03:27)

seth

Member

Registered: 2012-09-03

Posts: 62,183

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

        Size: 8 GB
        Speed: 800 MT/s
        Configured Memory Speed: 1066 MT/s

        Size: 4 GB
        Speed: 667 MT/s
        Configured Memory Speed: 1066 MT/s

        Size: 8 GB
        Speed: 800 MT/s
        Configured Memory Speed: 1066 MT/s

        Size: 4 GB
        Speed: 667 MT/s
        Configured Memory Speed: 1066 MT/s

Change the RAM timing in the BIOS to the most conservative values.

Edit: 'key you figured that yourself ;-)

Last edited by seth (2022-07-11 07:09:40)

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rajhlinux

Member

Registered: 2022-07-08

Posts: 58

Re: [SOLVED] - Arch Linux shows 3.8GB RAM when I have 24GB RAM installed

        Size: 8 GB
        Speed: 800 MT/s
        Configured Memory Speed: 1066 MT/s

        Size: 4 GB
        Speed: 667 MT/s
        Configured Memory Speed: 1066 MT/s

        Size: 8 GB
        Speed: 800 MT/s
        Configured Memory Speed: 1066 MT/s

        Size: 4 GB
        Speed: 667 MT/s
        Configured Memory Speed: 1066 MT/s

Change the RAM timing in the BIOS to the most conservative values.

Edit: 'key you figured that yourself ;-)

Not sure how to properly custom set the RAM timings on BIOS (always procrastinated to do it someday, even with the fact I am using performance DDR3 RAM sticks.), I will google it on how it's done.

Thank You.