Only Half of Installed Memory Detected - TrueNAS 25.10.3

TrueNAS General
1

Hello,
I am new to TrueNAS and am running into issues with only half my RAM being detected in my TrueNAS install (TrueNAS 25.10.3 Scale). Is there something I need to configure in the UI to use all the RAM I have?

More Details
I have 4 RAM sticks that are 8 GB each that were in dual module kits, though not from the same vendor or package. This should give me 32ish GB in TrueNAS, however, only 15.6 GB is available.

I tried running free to show the current memory usage and it shows that only 16 GB is available.

               total        used        free      shared  buff/cache   available
Mem:        16329224     1907632    14511312        6708      158152    14421592
Swap:              0           0           0

Then, I tried running sudo dmidecode -t 17 to display the hardware information of my installed RAM. From the data, it looks like all four modules are detected.

# dmidecode 3.4
Getting SMBIOS data from sysfs.
SMBIOS 3.0.0 present.

Handle 0x002E, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0027
        Error Information Handle: 0x002D
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 8 GB
        Form Factor: DIMM
        Set: None
        Locator: DIMM 0
        Bank Locator: P0 CHANNEL A
        Type: DDR4
        Type Detail: Synchronous Unbuffered (Unregistered)
        Speed: 2133 MT/s
        Manufacturer: Unknown
        Serial Number: 00000000
        Asset Tag: Not Specified
        Part Number: F4-3400C16-8GTZ
        Rank: 2
        Configured Memory Speed: 2133 MT/s
        Minimum Voltage: 1.2 V
        Maximum Voltage: 1.2 V
        Configured Voltage: 1.2 V

Handle 0x0031, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0027
        Error Information Handle: 0x0030
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 8 GB
        Form Factor: DIMM
        Set: None
        Locator: DIMM 1
        Bank Locator: P0 CHANNEL A
        Type: DDR4
        Type Detail: Synchronous Unbuffered (Unregistered)
        Speed: 2133 MT/s
        Manufacturer: Unknown
        Serial Number: 00000000
        Asset Tag: Not Specified
        Part Number: F4-3400C16-8GTZ
        Rank: 2
        Configured Memory Speed: 2133 MT/s
        Minimum Voltage: 1.2 V
        Maximum Voltage: 1.2 V
        Configured Voltage: 1.2 V

Handle 0x0034, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0027
        Error Information Handle: 0x0033
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 8 GB
        Form Factor: DIMM
        Set: None
        Locator: DIMM 0
        Bank Locator: P0 CHANNEL B
        Type: DDR4
        Type Detail: Synchronous Unbuffered (Unregistered)
        Speed: 2133 MT/s
        Manufacturer: Unknown
        Serial Number: 00000000
        Asset Tag: Not Specified
        Part Number: CMK8GX4M1D3000C16   
        Rank: 1
        Configured Memory Speed: 2133 MT/s
        Minimum Voltage: 1.2 V
        Maximum Voltage: 1.2 V
        Configured Voltage: 1.2 V

Handle 0x0037, DMI type 17, 40 bytes
Memory Device
        Array Handle: 0x0027
        Error Information Handle: 0x0036
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 8 GB
        Form Factor: DIMM
        Set: None
        Locator: DIMM 1
        Bank Locator: P0 CHANNEL B
        Type: DDR4
        Type Detail: Synchronous Unbuffered (Unregistered)
        Speed: 2133 MT/s
        Manufacturer: Unknown
        Serial Number: 00000000
        Asset Tag: Not Specified
        Part Number: CMK8GX4M1D3000C16   
        Rank: 1
        Configured Memory Speed: 2133 MT/s
        Minimum Voltage: 1.2 V
        Maximum Voltage: 1.2 V
        Configured Voltage: 1.2 V

I have already tried rearranging the RAM and currently there is no effect. I tried arranging them in an alternating pattern among the four slots and with RAM modules in side-by-side pairs.

If there is anything else I can do or show, please let me know. Thanks!

2

Do you see all the RAM when you boot into the BIOS. TrueNAS should not have anything to do with RAM that is missing. Review your Motherboard documenation
Posting full details on your system hardware may help others review it.

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3

Thanks SmallBarky! I will try checking if the BIOS detects the RAM (need to find and install a GPU to boot into BIOS since it is headless right now without onboard video). Last time I did have GPU installed, it did detect all four modules.

Is there a reason for the modules to be listed in the dmidecode command but not being detected by the motherboard? To me, it looked like the motherboard did detect the RAM but TrueNAS did not.

4

You could share the hardware you are using, what MB specifically are you using?. You already posted the RAM module data.

1 Like
5

Sure thing! The motherboard is a Gigabyte GA-AX370-Gaming K5 (Rev. 1.x).

6

The CPU is a AMD Ryzen 5 1500X Quad-Core Processor, which lacks integrated graphics. I am still working on finding a GPU to view the BIOS read out.

7

Looks like the MB has built in graphics. It does read kind of funny but if you haven’t tried the HDMI connection yet, I’d give it a shot.

1 Like
8

Mmmm i think you are wrong :innocent:

Backing on topic…

F4-3400C16-8GTZ
...
Rank: 2

CMK8GX4M1D3000C16
...
Rank: 1

IMHO in my little experience mixing single and dual rank modules can lead to training issue, you have probably a channel disabled from your motherboard to prevent boot failure.
If you plug another OS you will notice the same situation

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9

If you look at the QVL for this MB for Summit Ridge- CPUS, it says only two memory sockets are supported with some 8GB modules.

image
image2416Ă—502 93.7 KB

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10

Yeah, I wish it was that simple. I did try that a couple of times plugging directly into the HDMI port with a functioning monitor but no video.

11

Thanks for letting me know about single vs dual rank RAM modules. I haven’t heard of that before.

I see. This would mean a hardware issue then. Thanks!

12

I have checked that list now and it does look like a hardware incompatibility issue. Thanks!

13

Thanks to everyone for the help with the discussion. I believe my next steps are to get compatible RAM or running my NAS with 16 GB (the more likely option unfortunately).

This is an issue with my hardware and not an issue in TrueNAS itself.

Thanks again!

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14

And don’t forget get bios tweaks for First Gen ryzen CPUs, if you don’t do them your system is likely to hard lock itself after some uptime

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15

Rather, it has a video output for the iGPU… if the CPU has one. So no luck here.

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16

Yup, that is why I said the User Manual was a bit funky, it did not really specify that, not clearly to me. It said Integrated Graphics or something like that. Wishful thinking I guess.

Sorry it was a hardware issue that isn’t fixable without more hardware.

1 Like
17

Well, there’s “Gaming” in the product name so I guess we cannot expect a BMC, a block diagram in the manual, or even any kind of technically helpful manual, can we?

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18

#StopHardwareDiscrimination #BornGamingButFeelNAS"

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