How do I determine the number of RAM slots in use?

Question

How do I determine the number of RAM slots in use?

I forgot how many RAM (DIMM) modules are installed on my laptop. I do not want to unscrew it but want to look it up on the console using bash. How do I gather this information?

Asked By: k0pernikus

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Source

Answer 1

Since you don’t mention, I’m assuming this is on Linux. Any of the following should show you (with root):

dmidecode -t memory

dmidecode -t 16

lshw -class memory

Answered By: Chris Down

Answer 2

In my case,

sudo dmidecode -t 16

reports this:

Handle 0x000A, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 16 GB
        Error Information Handle: Not Provided
        Number Of Devices: 2

I would like to point out that I have only 4 GiB of RAM in one module. That info is shown by doing:

 sudo dmidecode -t 17

this is shown:

# dmidecode 2.11
SMBIOS 2.7 present.

Handle 0x000B, DMI type 17, 34 bytes
Memory Device
    Array Handle: 0x000A
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: ChannelA-DIMM0
    Bank Locator: BANK 0
    Type: Unknown
    Type Detail: None
    Speed: Unknown
    Manufacturer: Not Specified
    Serial Number: Not Specified
    Asset Tag: None
    Part Number: Not Specified
    Rank: Unknown
    Configured Clock Speed: Unknown

Handle 0x000C, DMI type 17, 34 bytes
Memory Device
    Array Handle: 0x000A
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 4096 MB
    Form Factor: SODIMM
    Set: None
    Locator: ChannelB-DIMM0
    Bank Locator: BANK 2
    Type: DDR3
    Type Detail: Synchronous
    Speed: 1600 MHz
    Manufacturer: Hynix/Hyundai
    Serial Number: 11111111
    Asset Tag: None
    Part Number: HMT351S6CFR8C-PB  
    Rank: Unknown
    Configured Clock Speed: 1600 MHz

And, as you can see, Bank 2 is full and Bank 0 empty. Board has only two slots for RAM, but they have to be double channel.

Answered By: Josep

Answer 3

Let’s make it easy for the not so shell-savvy users:

sudo dmidecode -t memory | grep -i size

The output on my laptop would be:

Size: 2048 MB
Size: 1024 MB

…showing that I have one 1GB module and one 2GB module installed.

Answered By: carsten

Answer 4

Even though the OP prefers to avoid unscrewing to physically inspect, I strongly suggest everyone do just that since the answer back from command line probes can be misleading. On my laptop, command line probes say I have 4 slots (2 used, 2 empty), yet upon unscrewing I actually have 2 slots (perhaps I have 2 hidden slots elsewhere yet not visible removing bottom panel) :

sudo dmidecode | grep -A 9 "System Information"
System Information
    Manufacturer: Micro-Star International Co., Ltd.
    Product Name: CX61 0NC/CX61 0ND/CX61 0NF/CX61 0NE
    Version: REV:1.0
    Serial Number: FFFFFFFF
    UUID: 03000200-0400-0500-0006-000700080009
    Wake-up Type: Power Switch
    SKU Number: To be filled by O.E.M.
    Family: To be filled by O.E.M.


# -------

sudo dmidecode -t 16
# dmidecode 2.12
SMBIOS 2.7 present.

Handle 0x0024, DMI type 16, 23 bytes
Physical Memory Array
    Location: System Board Or Motherboard
    Use: System Memory
    Error Correction Type: None
    Maximum Capacity: 32 GB
    Error Information Handle: Not Provided
    Number Of Devices: 4


# -------


sudo dmidecode -t 17
# dmidecode 2.12
SMBIOS 2.7 present.

Handle 0x0025, DMI type 17, 34 bytes
Memory Device
    Array Handle: 0x0024
    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: 1600 MHz
    Manufacturer: 830B
    Serial Number: 91D82E7B
    Asset Tag: 9876543210
    Part Number: M2S4G64CB8HG4N-DI 
    Rank: 2
    Configured Clock Speed: 1600 MHz

Handle 0x0027, DMI type 17, 34 bytes
Memory Device
    Array Handle: 0x0024
    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: [Empty]
    Serial Number: [Empty]
    Asset Tag: 9876543210
    Part Number: [Empty]
    Rank: Unknown
    Configured Clock Speed: Unknown

Handle 0x0028, DMI type 17, 34 bytes
Memory Device
    Array Handle: 0x0024
    Error Information Handle: Not Provided
    Total Width: 64 bits
    Data Width: 64 bits
    Size: 4096 MB
    Form Factor: SODIMM
    Set: None
    Locator: ChannelB-DIMM0
    Bank Locator: BANK 2
    Type: DDR3
    Type Detail: Synchronous
    Speed: 1600 MHz
    Manufacturer: 830B
    Serial Number: 20DC2E7C
    Asset Tag: 9876543210
    Part Number: M2S4G64CB8HG4N-DI 
    Rank: 2
    Configured Clock Speed: 1600 MHz

Handle 0x002A, DMI type 17, 34 bytes
Memory Device
    Array Handle: 0x0024
    Error Information Handle: Not Provided
    Total Width: Unknown
    Data Width: Unknown
    Size: No Module Installed
    Form Factor: DIMM
    Set: None
    Locator: ChannelB-DIMM1
    Bank Locator: BANK 3
    Type: Unknown
    Type Detail: None
    Speed: Unknown
    Manufacturer: [Empty]
    Serial Number: [Empty]
    Asset Tag: 9876543210
    Part Number: [Empty]
    Rank: Unknown
    Configured Clock Speed: Unknown

ubuntu 14.04

Answered By: Scott Stensland

Answer 5

[root@kr0 ~]# lsmem
RANGE                                 SIZE  STATE REMOVABLE BLOCK
0x0000000040000000-0x000000063fffffff  24G online       yes  1-24

Memory block size:         1G
Total online memory:      24G
Total offline memory:      0B

Answered By: bin456789