Command Center

How do I find out or identify the speed of my memory (DIMM) through command prompt options under Linux operating systems? How do I find out speed of the DIMM's using a shell prompt?

You can find out the speed using dmidecode or lshw command under any Linux distribution.
Install lshw

If you are using Debian / Ubuntu Linux, enter:
# apt-get install lshw
If you are RHEL / Fedora / Red Hat / CentOS Linux, enter the following after enabling EPEL repo:
# yum install lshw
How do I use lshw to display DIMM speed?

Type the command as follows:
# lshw -short -C memory
Outputs:

H/W path Device Class Description
=======================================================
/0/0 memory 108KiB BIOS
/0/4/6 memory 16KiB L1 cache
/0/4/7 memory 8MiB L2 cache
/0/5/8 memory 16KiB L1 cache
/0/5/9 memory 8MiB L2 cache
/0/16 memory 12GiB System Memory
/0/16/0 memory 2GiB DIMM Synchronous 667 MHz (1.5 ns)
/0/16/1 memory 2GiB DIMM Synchronous 667 MHz (1.5 ns)
/0/16/2 memory 2GiB DIMM Synchronous 667 MHz (1.5 ns)
/0/16/3 memory 2GiB DIMM Synchronous 667 MHz (1.5 ns)
/0/16/4 memory 2GiB DIMM Synchronous 667 MHz (1.5 ns)
/0/16/5 memory DIMM Synchronous 667 MHz (1.5 ns) [empty]
/0/16/6 memory 2GiB DIMM Synchronous 667 MHz (1.5 ns)
/0/16/7 memory DIMM Synchronous 667 MHz (1.5 ns) [empty]

See how to use dmidecode to find out RAM speed and type under Linux.

Reference: http://www.cyberciti.biz/faq/linux-find-memory-speed-dimm-command/