Definition: Gbps

(GigaBits or GigaBytes per Second) One billion bits or bytes per second. The correct abbreviation is "b" for bits and "B" for bytes; however, "b" and "B" are often erroneously interchanged. See space/time, Mbps and Kbps.

Gigabits - "b" (Gbps, Gb/sec, Gb/s)
Gigabits per second is used to rate high-speed serial data transfers such as SATA, SAS and USB and high-speed network transmission such as Gigabit and 10 Gigabit Ethernet.

Gigabytes - "B" (GBps, GB/sec, GB/s)
Gigabytes per second is used to rate high-speed parallel data transfers such as memory-to-memory and PCI Express.