Ethernet is synonymous with Gigabit Ethernet, which supports network speeds up to one Gigabit per second (1Gbps), but the 2.5G, 5G, and 10G standards are starting to arrive on mainstream routers. These provide speeds of up to 2.5Gbps, 5Gbps, or even 10Gbps, respectively.  While fast, Ethernet standards beyond Gigabit Ethernet aren't useful for most people because few internet providers offer service that can exceed one Gigabit.  However, this feature could be useful if you have a wired home network that you use to transfer files between computers, and it becomes a necessity if you're among the lucky few with access to superfast fiber internet.