The high-speed I/O device known as Thunderbolt was created by Intel and Apple. It enables both data devices and screens and is built on the PCI Express and DP technologies. While the third and fourth versions of Thunderbolt use a USB-C connection, the first two generations use a Mini DisplayPort socket.

External devices linked via Thunderbolt can now reach speed that was previously only achievable from interior components because Thunderbolt is built on the PCI Express design. Thunderbolt's first-generation interface had a speed of 10 Gbps in both ways, which subsequently increased to 40 Gbps in third- and fourth-generation links, which is eight times as fast as USB 3.0 and four times as fast as USB 3.1.

Similar to USB and FireWire, Thunderbolt can supply electricity to attached auxiliary devices. For first- and second-generation links, this power can reach 10 watts, while third- and fourth-generation Thunderbolt can reach 100 watts. The Thunderbolt connection can now be used to supply electricity straight to peripheral devices like displays and external storage devices. Furthermore, straightforward converters can link Ethernet, FireWire, and USB devices to a Thunderbolt connection.

Thunderbolt can be used to link to high-resolution screens even though its primary use is as a high-speed data port. Since the Mini-DisplayPort interface and the first- and second-generation Thunderbolt interface are practically similar, a DisplayPort display can be connected using either one. The third- and fourth-generation Thunderbolt link transmits DisplayPort data over a USB-C connection instead, which is less prevalent but accepted by some displays. Similar to HDMI, DisplayPort allows both audio and video, so an additional audio connection is not necessary.

Daisy-chaining allows numerous Thunderbolt devices to be connected in succession to a single Thunderbolt interface. For instance, you could attach a Thunderbolt portable hard disk to a computer and a Thunderbolt monitor to the computer. A second Thunderbolt device could also be connected to the primary display. This indicates that you can attach two additional monitors to a laptop provided it has the density needed for two panels.