Thunderbolt is an Intel/Apple protocol that runs over USB-C, supporting up to 80 Gbps bandwidth with Thunderbolt 5. Enables external GPUs, fast storage, and multi-4K displays.
Thunderbolt versions and bandwidth: Thunderbolt 3 / 4: 40 Gbps per direction (80 Gbps bidirectional). TB4 is the PCIe Gen 4 version. Thunderbolt 5: 80 Gbps per direction (160 Gbps bidirectional). PCIe Gen 5 based, released 2024. Thunderbolt 5 Bandwidth Boost: optional mode reaching 120 Gbps per direction for simultaneous video + data at peak throughput.
Unlike USB-C which is just a connector, Thunderbolt requires an Intel/Apple silicon controller — not all USB-C ports are Thunderbolt.
Key advantages over USB: Thunderbolt supports eGPU (external GPU enclosures), dual 6K or quad 4K displays simultaneously, and blazing-fast external SSD speeds (sustained 2000+ MB/s real-world). USB-C can do some of this via DP Alt Mode, but Thunderbolt is more reliable and higher bandwidth.
Common Thunderbolt devices: CalDigit external RAID SSDs (2400+ MB/s), Blackmagic external GPU docks, LG UltraFine 5K displays (built-in Thunderbolt dock).
Availability: MacBook Pro (all models since 2016), Dell XPS 15/17, ThinkPad X1 Extreme, Lenovo Legion Slim. Budget laptops skip Thunderbolt due to cost of the controller.