Linux - Is there any way to identify the speed of your memory through software?

dmidecode is the tool you're looking for.

On my Debian, lshw give me that information.

# lshw -version
B.02.13
# lshw -short -C memory
H/W path             Device     Class       Description
=======================================================
/0/1                            memory      128KiB BIOS
/0/5/6                          memory      20KiB L1 cache
/0/5/7                          memory      1MiB L2 cache
/0/27                           memory      System Memory
/0/27/0                         memory      256MiB DIMM DDR Synchronous 400 MHz (2.5 ns)
/0/27/1                         memory      256MiB DIMM DDR Synchronous 400 MHz (2.5 ns)
/0/27/2                         memory      256MiB DIMM DDR Synchronous 266 MHz (3.8 ns)
/0/27/3                         memory      256MiB DIMM DDR Synchronous 400 MHz (2.5 ns)
/0/28                           memory      Flash Memory
/0/28/0                         memory      512KiB Chip FLASH Non-volatile
/0/0                            memory      
/0/2                            memory      

Can you post your output of dmidecode for the memory section? (dmidecode --type memory)

You might want to read this: http://www.howtoforge.com/dmidecode-finding-out-hardware-details-without-opening-the-computer-case

The "NS" references "nanosecond" the speed in which the memory is able to reply. The lower the number the faster the speed. Unfortunately this doesn't reference an exact Mhz number. DMIDECODE is supposed to output the Mhz as well. Check at the very bottom of the output or simply dmidecode --type memory | grep Mhz