GB
gigabytes or gigabits - see MB. Giga stands for 10^9 - a US billion, or in computing for 2^30.
The text of a thirty volume encyclopaedia would require about one gigabyte of ASCII storage.
Gb
Gigabit. 10^9 bits. Might also be wrongly used for gigabyte (GB).
gb
(Great Britain) A country code for United Kingdom. "uk" is generally used instead.