For many years, data transfer speeds were only measured in Mbps and Kbps. However, modern hardware interfaces can now transfer data over one gigabit per second, which makes Gbps a necessary unit of measurement. Examples of these interfaces include SATA 3 (6Gbps), USB 3.0 (5Gbps), and Thunderbolt (10Gbps). Additionally, Gigabit Ethernet can transfer data up to 1Gbps.
NOTE: The lowercase "b" is Gbps indicates it stands for "Gigabits" rather than "Gigabytes." Since one byte equals eight bits, 1GBps is equal to 8Gbps. While storage capacity is typically measured in bytes, data transfer speeds are typically measured in bits. Therefore, Gbps is much more commonly used than GBps.