Checking if RAM works in dual-channel mode on Linux

Question

I bought a second SO-DIMM for my Dell Latitude 5420 and want to check if the RAM works in dual-channel mode now. Everyone suggests using dmidecode to figure this out, but my output differs from what other people have. But it also differs from single-channel-only laptop I had before, so I don't know how to interpet it. Can someone help? Here's the output of sudo dmidecode -t memory:

# dmidecode 3.3
Getting SMBIOS data from sysfs.
SMBIOS 3.2 present.

Handle 0x1000, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 128 GB
        Error Information Handle: Not Provided
        Number Of Devices: 2

Handle 0x1100, DMI type 17, 92 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 16 GB
        Form Factor: SODIMM
        Set: None
        Locator: DIMM B
        Bank Locator: BANK 0
        Type: DDR4
        Type Detail: Synchronous
        Speed: 3200 MT/s
        Manufacturer: 01980000802C
        Serial Number: CEB33182
        Asset Tag: 07213400
        Part Number: 9905744-077.A00G
        Rank: 2
        Configured Memory Speed: 3200 MT/s
        Minimum Voltage: Unknown
        Maximum Voltage: Unknown
        Configured Voltage: 1.2 V
        Memory Technology: DRAM
        Memory Operating Mode Capability: Volatile memory
        Firmware Version: Not Specified
        Module Manufacturer ID: Bank 2, Hex 0x98
        Module Product ID: Unknown
        Memory Subsystem Controller Manufacturer ID: Unknown
        Memory Subsystem Controller Product ID: Unknown
        Non-Volatile Size: None
        Volatile Size: 16 GB
        Cache Size: None
        Logical Size: None

Handle 0x1104, DMI type 17, 92 bytes
Memory Device
        Array Handle: 0x1000
        Error Information Handle: Not Provided
        Total Width: 64 bits
        Data Width: 64 bits
        Size: 16 GB
        Form Factor: SODIMM
        Set: None
        Locator: DIMM A
        Bank Locator: BANK 0
        Type: DDR4
        Type Detail: Synchronous
        Speed: 3200 MT/s
        Manufacturer: 80AD000080AD
        Serial Number: 2371A7C9
        Asset Tag: 02211100
        Part Number: HMAA2GS6AJR8N-XN
        Rank: 1
        Configured Memory Speed: 3200 MT/s
        Minimum Voltage: Unknown
        Maximum Voltage: Unknown
        Configured Voltage: 1.2 V
        Memory Technology: DRAM
        Memory Operating Mode Capability: Volatile memory
        Firmware Version: Not Specified
        Module Manufacturer ID: Bank 1, Hex 0xAD
        Module Product ID: Unknown
        Memory Subsystem Controller Manufacturer ID: Unknown
        Memory Subsystem Controller Product ID: Unknown
        Non-Volatile Size: None
        Volatile Size: 16 GB
        Cache Size: None
        Logical Size: None

As you can see, the sticks are in one bank, but in different locators. Does that mean they're running in single-channel, or dual-channel mode? Or is there some other way to find this out?

Edit: The BIOS photo - well, that was easy. Thanks, Dell! And Mokubai, of course, for pointing me to an obvious solution :)

Performance in games became noticeably better (dual-channel RAM is important for integrated GPU, AFAIK), so I guess that means that the RAM is in dual-channel mode now. Still would like to know how to interpret dmidecode output, though :) — Discussian, Sep 29 '21 at 16:55
Everything I can see suggests that there should be a "channel" indicator. Lacking that Memtest86 should tell you: https://superuser.com/a/1621323/19943 — Mokubai, Sep 29 '21 at 16:59
Otherwise your system firmware might give some indication of memory modes: https://superuser.com/a/426474/19943 — Mokubai, Sep 29 '21 at 17:01

Tamal Mallick · Answer 1 · 2023-01-06T17:11:21.620

Open the terminal and just run :

sudo dmidecode -t 17 | awk 'BEGIN { FS=":"; OFS="\t" } /Size|Channel/ { line = (line ? line OFS : "") $2 } /^$/ { print line; line="RAM" }' | grep -iv 'no'

Case 1 :

(output as)

RAM 4 GB ChannelA-DIMM0

RAM 4 GB ChannelB-DIMM0

-> Means using 2 channels channel A & B (If your system is using more channels it may include say ChannelC ,ChannelD...)

Case 2:

(No output)

-> Means, your system is using a single channel

Checking if RAM works in dual-channel mode on Linux

1 Answers1