TL;DR

• USB 2.0: 480 Mb/s (≈60 MB/s). Legacy keyboards, mice, audio, many flash drives.
• USB 3.2 Gen 1 (USB 3.0): 5 Gb/s (≈450 MB/s real). Blue Type‑A most common.
• USB 3.2 Gen 2: 10 Gb/s (≈900 MB/s real). Often Type‑C; some A.
• USB 3.2 Gen 2x2: 20 Gb/s (≈1.8 GB/s real). Requires C‑to‑C + proper cable/hub.
• USB4: 20/40 Gb/s. May tunnel PCIe/DisplayPort; depends on device.
• Thunderbolt 3/4: 40 Gb/s. All TB4 = USB4 compliant; stricter hub/port rules.

Connectors vs Versions

• Connector ≠ Speed. Type‑C can be slow (USB 2.0) or very fast (USB4/TB).
• Check the port symbol and spec sheet; cables matter.

Cables Matter

• Use e‑marked C cables for 100 W/240 W PD or 20/40 Gb/s.
• Old/cheap C cables may limit to USB 2.0 or 3.2 Gen 1.

Display Support (quick cues)

• Look for the DP logo on ports/cables for video over USB‑C.
• USB4/TB docks typically support multiple 4K displays; USB 3.x “alt‑mode” often 1× 4K.

Buying Advice

• For new gear: aim for USB‑C with USB4/TB4 if displays or fast storage matter.
• For basic peripherals, USB 3.2 Gen 1 is plenty.