How to check RAM details

Page will be interest those who want to find information regarding what RAM exists on their system and what compatible upgrades they can get. Examples below were run on a Dell PowerEdge R620 host, mem.

Finding out how much RAM you can get

Use dmidecode -t memory | less to see useful information regarding what your computer can be upgraded to and what currently exists on your system.

The first section of the output will show you what sort of memory to use, the maximum memory you can install, and the number of RAM sticks you can use.

dmidecode -t memory
Handle 0x1000, DMI type 16, 23 bytes
Physical Memory Array
       Location: System Board Or Motherboard
       Use: System Memory
       Error Correction Type: Multi-bit ECC
       Maximum Capacity: 768 GB
       Error Information Handle: Not Provided
       Number Of Devices: 24

From this output, we can see that the RAM sticks this motherboard supports are registered ECC (as is common with most servers). It supports a maximum of 768 GB over 24 slots which comes down to 32GB per slot. I know that this host has 2 processors which are Xeon E5-2680. If you look up the processor, you can see that each processor supports up to 384 GB RAM. So, 768 GB for the whole machine makes sense.

The next section of the dmidecode output show what exists in each slot. The output here corresponds to ram slot with an 8GB DDR3 stick from Hynix:

# Below information we can see total width is 8 bits bigger than data width which indicates it is ECC memory (the additional 8 bits are designed for error correction checking).  
# It has a size of 8192 MB indicating 8 GB.  
# It's DDR3 SDRAM that runs at 1600 MHz.  
# The manufacturer name sometimes shows up as an actual company name (ie Samsung/Crucial/Kingston) but sometimes it comes out as gibberish like below
# Searching the part number online will usually yield the actual product
Handle 0x1100, DMI type 17, 34 bytes
Memory Device
       Array Handle: 0x1000
       Error Information Handle: Not Provided
       Total Width: 72 bits
       Data Width: 64 bits
       Size: 8192 MB
       Form Factor: DIMM
       Set: 1
       Locator: DIMM_A1 
       Bank Locator: Not Specified
       Type: DDR3
       Type Detail: Synchronous Registered (Buffered)
       Speed: 1600 MHz
       Manufacturer: 00AD00B300AD
       Serial Number: 35AB5CF9
       Asset Tag: 01124263
       Part Number: HMT31GR7CFR4C-PB  
       Rank: 2
       Configured Clock Speed: 1600 MHz

If the RAM slot is empty, it will look like this:

# (Empty RAM Slot)
Handle 0x1108, DMI type 17, 34 bytes
Memory Device
       Array Handle: 0x1000
       Error Information Handle: Not Provided
       Total Width: 72 bits
       Data Width: 64 bits
       Size: No Module Installed
       Form Factor: DIMM
       Set: 3
       Locator: DIMM_A9 
       Bank Locator: Not Specified
       Type: DDR3
       Type Detail: Synchronous
       Speed: Unknown
       Manufacturer:             
       Serial Number:         
       Asset Tag:         
       Part Number:                   
       Rank: Unknown
       Configured Clock Speed: Unknown