Thunderbolt 2 supports twice the bandwidth, a stunning 20Gbps. Beyond that, Thunderbolt 2 is no longer two independent 10Gbps channels but instead uses one 20Gbps bi-directional channel that supports data and/or display.
In other words, video editors can transfer 4K footage and playback that footage at the same time. That’s simply not available on any other interface.
Thunderbolt 2 will also add in support for DisplayPort 1.2, which offers 4K streaming.
Thunderbolt 2 is backwards compatible with old cables and connectors, so users who have already adopted Thunderbolt don’t need to worry about buying new cables for their gear.