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USB-C hub bandwidth calculator: will 4K video and a fast SSD fit through one port?

A hub does not add bandwidth; it divides the one port you plug it into. The display and the USB ports share the same four high-speed lanes, and the split depends on the port and the screen. Pick yours and see what is left.

1. The port on your laptop

A lightning-bolt symbol next to the port means Thunderbolt. Not sure? How to check what your port can do.

2. The display you want through the hub

The hub's listing says DP 1.4, HBR3, or “4K 60Hz and 10 Gb/s USB”Most hubs are DP 1.2. Leave this off unless the listing says so.

3. What else goes through the hub

Display

Fits

Takes 4 of the port's 4 high-speed lanes.

Hub's USB ports

USB 2.0 (480 Mb/s)

Shared by everything plugged in. An external SSD gets about 35 MB/s — your devices ask for 4.5 Gb/s, more than the link has, so they slow each other down.

• 4K at 60Hz needs all four high-speed lanes on a plain USB-C port, so every USB port on the hub falls back to USB 2.0 (480 Mb/s). A hub that lists "DP 1.4" or "4K 60Hz with 10 Gb/s USB" avoids this.

Charging through the hub has its own limits: why laptops charge slowly through a hub.

Hubs we have reviewed that list 4K 60Hz

Questions this answers

Why do my hub's USB ports become slow when a 4K monitor is connected?

A USB-C port has four high-speed lanes shared between DisplayPort video and USB 3. A 4K 60Hz signal needs all four on most hubs, so USB falls back to USB 2.0 at 480 Mb/s — about 35 MB/s for a drive. At 4K 30Hz or 1440p 60Hz the video takes two lanes and USB 3 keeps the other two.

How do I get 4K 60Hz and fast USB from the same hub?

Either a Thunderbolt or USB4 port and dock, where video is carried separately inside a 40 Gb/s link, or a hub whose listing says DP 1.4 / HBR3 — those carry 4K 60Hz on two lanes and keep 10 Gb/s USB. A hub that only says "4K" usually means 4K 30Hz.

What speed will an external SSD get through a hub?

Roughly 400 MB/s on a 5 Gb/s link, 900 MB/s on 10 Gb/s, and about 35 MB/s if the link has fallen to USB 2.0. An NVMe enclosure on a 5 Gb/s hub runs no faster than a SATA SSD.

Does a hub add bandwidth?

No. Every port on the hub shares what the laptop's single port provides. A hub with seven ports and a hub with three ports have the same total to divide.

Figures are the USB and DisplayPort specifications (lane payload after 8b/10b coding, typical transfer rates after protocol overhead), not measurements of any product. Hubs listed are reviews on this site, filtered by what their listing title claims. See also the monitor compatibility checker.