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Fedora 14 HP Netbook 210 Mini

My netbook had 1 GB of DDR3 memory. However, that wasn't enough. So I decided to replace the 1 GB with a 2GB or DDR3.

However, what command can I issue to be sure that I am using DDR3.

I tried the following cat /proc/meminfo

However, it didn't list any information about DDR3.

Is there some other command I can use?

Many thanks for any suggestions.

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1  
Have you tried dmidecode? –  Malabarba Dec 11 '10 at 6:20

4 Answers 4

up vote 5 down vote accepted

Running dmidecode or lshw should show the type. Might require root privileges to check, however.

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Found it using dmidecode. However, lshw return 'command not found'. –  ant2009 Dec 11 '10 at 7:32
    
It is well known that dmidecode is inaccurate in reporting memory information. See here –  David Schwartz Jan 12 '12 at 0:49
    
@DavidSchwartz, your comment is wrong and your link is dead. Instead of posting such tiny comments, consider posting an answer of your own with more details than can fit in the tiny comment field. :) (For example, if dmidecode were inaccurate, what would you use instead? That would make a good answer.) –  Quuxplusone Mar 17 at 23:32
    
@Quuxplusone The comment was correct and the link was live when it was made. Unfortunately, you can't edit comments years later, so it's impossible to keep them up to date. If I had better information at the time, I would have left an answer rather than just a comment. But I didn't, and I felt it was important to warn anyone reading the answer that they couldn't rely on the information dmidecode gives. –  David Schwartz Mar 17 at 23:51

According to http://askubuntu.com/questions/18372/how-can-i-find-out-what-ram-a-computer-system-has , the one-liner you're looking for is

sudo lshw -short -C memory

This will spit out something along the lines of

H/W path              Device     Class          Description
===========================================================
/0/0                             memory         64KiB BIOS
/0/4                             memory         256KiB L1 cache
/0/5                             memory         1MiB L2 cache
/0/6                             memory         8MiB L3 cache
/0/7                             memory         8200MiB System Memory
/0/7/0                           memory         4GiB DIMM DDR3 Synchronous
/0/7/1                           memory         DIMM [empty]
/0/7/2                           memory         4GiB DIMM DDR3 Synchronous
/0/7/3                           memory         DIMM [empty]
/0/7/4                           memory         8MiB FLASH

Be aware that the human-readable string (4GiB DIMM DDR3) is self-reported by the RAM and/or BIOS, so it isn't in any standardized format. If you're really lucky, it will explicitly say DDR3 or DDR4. Otherwise, if it indicates a frequency in MHz, you can try to distinguish based on that.

From Wikipedia:

DDR1: 2.5 V, 133–200 MHz
DDR2: 200–400 MHz
DDR3: 1.5 V, 400–800 MHz (up to 1400 MHz for super-high-end)
DDR4: 1.2 V, 2133–4266 MHz

For example: My other computer's DDR4 RAM shows up in lshw -short -C memory as simply 16GiB DIMM Synchronous 2133 MHz (0.5 ns). The MHz rating indicates that it's almost certainly DDR4.

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Use this to find type and speed of RAM on Linux:

sudo dmidecode --type 17|agrep -i 'speed|size|type'

Tested on Cent OS, Fedora, RHEL, Scientific Linux

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Here's the exact way to find out whether you have DDR2 or DDR3 Memory on Debian or Ubuntu systems:

sudo dmidecode | grep DDR

It will return something like this:

Type: DDR3

Or you can do this:

sudo lshw | grep DDR

It will return a bit more information, like this:

description: SODIMM DDR3 Synchronous 1600 MHz (0.6 ns)

You're welcome.

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As noted in the comment posted more than two years ago, to Sathya's answer posted more than three years ago, dmidecode is inaccurate. And lshw wouldn't work for the original poster. –  ChrisInEdmonton Apr 24 '14 at 0:12

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