Thunderbolt 4 is the latest generation of Thunderbolt.
Thunderbolt 4 ports are on all recent Mac computers, MacBook Air, MacBook, MacBook Pro and even on the latest iPad Pro. Thunderbolt 4 can also be found on recent PC's based around Intel's 11th Generation Core mobile processors, or PC's that are equipped with a Thunderbolt 4 controller.
Whilst it is easiest to think of Thunderbolt 3 and Thunderbolt 4 as being the same beasts, Thunderbolt 4 has delivered three new and important improvements or enhancements.
Thunderbolt 4 ports retain the same 40Gbps data transfer bandwidth as Thunderbolt 3.
The first improvement is that minimum PCIe data requirements have increased from 16Gbps to 32Gbps. This means that high-speed external PCIe devices like HomeKit Australia Thunderbolt Fire SSD drive and external graphics will see significant increases in data transfer rates and performance.
Second, VT-d based DMA protection that forms part of Thunderbolt 4, helps prevent security threats by remapping requests from external devices and checking for proper permissions.
And third, Thunderbolt 4 also adds "wake from sleep". Wake from sleep over Thunderbolt 4 allows a Mac, iPad or PC to resume processing with peripherals that are connected through a Thunderbolt 4 docking station.