Size of installed RAM vs what KInfocenter reports

[kubicle]

For DRAM the term gigabyte still commonly refers to 2^30. But that's not the point, for addressing reasons it does not make sense to make RAM in anything other than powers of 2; in my admittedly limited (but long) experience I've never heard of RAM being made otherwise. The OP's computer's RAM is very unlikely to be 7.6 GiB.

Yes, for technical reasons memory sticks are made in MiBs/GiBs (even if the term MB/GB is used...unlike hard disks).
sudo lshw -C memory should report a total of 8 GiBs of memory modules installed on the machine.

[Snowhog]

Yes, for technical reasons memory sticks are made in MiBs/GiBs (even if the term MB/GB is used...unlike hard disks).
sudo lshw -C memory should report a total of 8 GiBs of memory modules installed on the machine.

Which, here, reports:

sudo lshw -C memory

  *-memory
       description: System Memory
       physical id: 16
       slot: System board or motherboard
       size: 8GiB
     *-bank:0
          description: SODIMM DDR3 Synchronous 1067 MHz (0.9 ns)
          physical id: 0
          serial: FFFFFFFF
          slot: Bottom - Slot 1
          size: 4GiB
          width: 64 bits
          clock: 1067MHz (0.9ns)
     *-bank:1
          description: SODIMM DDR3 Synchronous 1067 MHz (0.9 ns)
          physical id: 1
          serial: FFFFFFFF
          slot: Bottom - Slot 2
          size: 4GiB
          width: 64 bits
          clock: 1067MHz (0.9ns)

[kubicle]

Yes, that would be 8 GiBs. Do note that all installed RAM is never available to an OS running on the machine as the hardware reserves some of the address space for itself (how much is reserved depends on the hardware, of course)