Thunderbolt vs USB | difference between Thunderbolt and USB

This page compares Thunderbolt vs USB and mentions difference between Thunderbolt and USB interface types. Thunderbolt 3 and USB-C are compared.

Thunderbolt interface

The Thunderbolt technology is transformational high speed, dual core I/O protocol which offers excellent performance over current I/O technologies available in market with 10 Gbps bi-directional speed. It supersedes Firewire interface.

It supports both data and video on single cable connection (with dual protocol viz. PCI express and DisplayPort) which can daisy chain upto 6 devices. Due to thunderbolt technology, it has become possible to connect laptops over single cable to high performance storage, display and multimedia devices. It is compatible with existing DisplayPort devices. It uses native PCIe and DisplayPort Protocol software drivers. It supports power over cable for bus powered devices.

There are different types of thunderbolt viz. Thunderbolt 1, Thunderbolt 2 and Thunderbolt 3. Thunderbolt -1 supports 10 Gbps bi-directional and dual channel data transfer. Thunderbolt-2 and Thunderbolt-3 supports 20 Gbps and 40 Gbps respectively.

USB interface

Different USB types based on shape/design of cable and port are type-A, type-B, type-C. The different USB versions based on their capabilities (speed/power) and cable are USB 1.1, USB 2.0, USB 3.0, USB 3.1 Gen.1 and USB 3.1 Gen. 2.

The above figure depicts connector types of USB 2.0 and USB 3.0. Following are the pin designations of USB type-c plug connector.

The USB Type-C design of connectors and cables mentioned in USB revision 3.1. Following are the features of USB-C.
• It supports data speed of 10Gbps.
• It supports max. power output of 20V/5A.
• Power direction is bi-directional.
• It is used in tablets, smartphones, laptops etc.
• It supports USB 2.0 LS/FS/HS capabilities.
• It supports EMI/RFI mitigation functionalities.

Difference between Thunderbolt and USB

Following table mentions similarities and difference between Thunderbolt and USB types.

Features	Thunderbolt 3	USB-C
Speed	Upto 40 Gbps	Upto 10 Gbps
Power	up to 100W	up to 100W
Distance	0.5 meters with 40 Gbps, 1-2 meters with 20 Gbps	Type-C supports Up to 1-2 meters with 20 Gbps ( USB 3.0 supports 3 meters, USB 2.0 supports 4 meters)
Display	Two 4K displays or one 5K display	One 4K display
Graphics (external)	It uses PCIe bus which enables use of eGPU.	It can not use eGPU.
Expansion	Daisy chain upto 6 devices	Can only connect one device
Device compatibility	• Thunderbolt-3 (other thunderbolt types using adapter) , • USB devices, • Legacy USB 3.x/2.x devices using adapter with speed as per device capabilities.	• USB-C devices, • legacy USB 3.x/2.x devices using adapter with speed as per device capabilities.• Note: It is not compatible with thunderbolt devices.

Thunderbolt 3 interface cable uses USB-C connector, but not all host connections/ cables/ devices with USB-C connector support Thunderbolt 3 interface.

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