Linux – memory and where is it

To find out what memory you have onboard and also where it is, here is a neat command

lshw -class memory

Here is my output

  *-firmware                                 
       description: BIOS
       vendor: Acer
       physical id: 0
       version: V2.04 (01/15/07)
       size: 103KiB
       capabilities: isa pci pcmcia pnp apm upgrade shadowing escd cdboot acpi usb agp biosbootspecification
  *-cache:0
       description: L1 cache
       physical id: 5
       slot: L1 Cache
       size: 16KiB
       capacity: 16KiB
       capabilities: asynchronous internal write-back
  *-cache:1
       description: L2 cache
       physical id: 6
       slot: L2 Cache
       size: 4MiB
       capabilities: burst external write-back
  *-memory
       description: System Memory
       physical id: 12
       slot: System board or motherboard
       size: 2GiB
     *-bank:0
          description: SODIMM Synchronous
          physical id: 0
          slot: M1
          size: 1GiB
          width: 32 bits
     *-bank:1
          description: SODIMM Synchronous
          physical id: 1
          slot: M2
          size: 1GiB
          width: 32 bits

I basically have 2GiB of memory and also L1 cache (on die cache on the cpu) of 16KiB and 4MiB L2 Cache.

Here is a wiki page that details what L1 and L2 cache are CPU cache, basically L1 means on CPU die, and L2 means slightly further away from the L1 cache. If there is a memory call L1 is the first hit, then L2 and then the memory and then swap space (harddrive), the lower down the line means slower result time.