Which Thunderbolt version supports an aggregated throughput of 40 Gbit/s?

Thunderbolt v3 is the version that supports an aggregated throughput of 40 Gbit/s. This capability is a significant advancement over earlier versions, as Thunderbolt v1 and v2 only offered a maximum throughput of 10 Gbit/s and 20 Gbit/s respectively. While Thunderbolt v1 uses the Mini DisplayPort connector, Thunderbolt v2 introduced a dual-protocol approach, which enabled the improved throughput but still fell short of the capability found in Thunderbolt v3.

Thunderbolt v3 brought not just an increase in speed, but also transitioned to a USB-C connector, allowing for greater compatibility with a wider range of devices. Additionally, Thunderbolt v3 maintains the Thunderbolt ecosystem's ability to daisy-chain multiple devices, further enhancing its utility in professional settings.

Thunderbolt v4 also supports 40 Gbit/s throughput but is built on the features and standards established by Thunderbolt v3. Emphasizing interoperability and ensuring a consistent performance across devices are key aspects of Thunderbolt v4; however, it is Thunderbolt v3 that was the first to introduce this specific throughput capability.