While Thunderbolt 4 won’t deliver any increase over the maximum 40 Gb/s available on Thunderbolt 3, there are some notable improvements such as universal cables up to two meters long without needing to resort to active cables that omit support for slower USB standards as on Thunderbolt 3, the ability to support docks and other accessories with up to four Thunderbolt 4 ports (one upstream, three downstream), and more.
Thunderbolt 4 certification requirements include:
- Double the minimum video and data requirements of Thunderbolt 3.
- Video: Support for two 4K displays or one 8K display.
- Data: PCIe at 32 Gbps for storage speeds up to 3,000 MBps.
- Support for docks with up to four Thunderbolt 4 ports.
- PC charging on at least one computer port.
- Wake your computer from sleep by touching the keyboard or mouse when connected to a Thunderbolt dock.
- Required Intel VT-d-based direct memory access (DMA) protection that helps prevent physical DMA attacks.
Thunderbolt 4 ports and cables are fully backward and cross-compatible with USB4, Thunderbolt 3, and other USB standards, and it continues to use the USB-C physical connector design.
Thunderbolt 4 will be coming first to Intel’s upcoming Tiger Lake processors for notebooks, with separate 8000-series controller chips coming later this year.
Apple, of course, has just announced that it will be transitioning away from Intel processors to its own Apple Silicon chips across its Mac lineup over the next couple of years, and it remains to be seen how Apple will handle Thunderbolt support going forward. The A12Z-based Mac mini units Apple is distributing to developers to help them prepare their apps for the transition do not include any Thunderbolt 3 ports.