sudo lshw -C memory

*-memory
       description: System Memory
       physical id: 1b
       slot: System board or motherboard
       size: 8GiB
     *-bank:0
          description: SODIMM DDR3 Synchronous 1334 MHz (0.7 ns)
          product: RMT3020EC58E9F1333
          vendor: Fujitsu
          physical id: 0
          serial: 415A7459
          slot: DIMM0
          size: 4GiB
          width: 64 bits
          clock: 1334MHz (0.7ns)
     *-bank:1
          description: SODIMM DDR3 Synchronous [empty]
          physical id: 1
          slot: DIMM1
     *-bank:2
          description: SODIMM DDR3 Synchronous 1334 MHz (0.7 ns)
          product: RMT3020EC58E9F1333
          vendor: Fujitsu
          physical id: 2
          serial: 41733A59
          slot: DIMM2
          size: 4GiB
          width: 64 bits
          clock: 1334MHz (0.7ns)
     *-bank:3
          description: SODIMM DDR3 Synchronous [empty]
          physical id: 3
          slot: DIMM3