USB-A and USB-C describe connector shapes. USB 2.0 runs at up to 480 Mbps. USB 3.0, USB 3.1 Gen 1 and USB 3.2 Gen 1 refer to 5 Gbps. USB 3.2 also has 10 and 20 Gbps modes. USB4 uses USB-C and can reach 20, 40 or 80 Gbps depending on implementation. USB 3.2 and USB4 at 20 Gbps use different protocols. Thunderbolt also uses USB-C on recent generations, with its own requirements.

Check data rate, video and power separately. A display requires a compatible video path such as DisplayPort Alt Mode, USB4 or Thunderbolt. For USB Power Delivery, check the supported wattage and direction. Real transfer speed is limited by the slowest part of the chain: port, cable, dock or drive. Check the spec for the exact port, including front-panel ports on desktops.

Smartphone charging explained: USB PD, PPS and Qi2