What implies the numbers at USB ports on MoBo?

Navin Talati

Posts: 63   +2
Internal USB ports on the motherboard are given and identified with some specific numbers. e.g. Asus M4A88T-M motherboard has THREE such internal ports which are USB connectors (10-1 pin USB78, USB910, USB1112). Here is the facility to connect the USB module cable to any of these connectors, then install the module to a slot opening at the back of the system chassis. These USB connectors comply with USB 2.0 specification that support to the 480 Mbps connection speed.
What information one may get from its numbers specified along with "USB" identification (I.e. USB78, USB910, USB1112 etc.)?


Posts: 1,881   +2,202
Staff member
The numbers after the USB part refers to the ports used by that connector in the main USB hub, so USB78 will use ports 7 and 8, and so on.

My PC uses an Asus Z390-Plus Gaming motherboard. The main USB Host Controller is the Intel one built into the Z390 chipset and it provides 26 ports.

The board has the following USB connectors on the back panel:

  • U31G2_12
  • U31G1_34

These are USB 3.1 sockets (four in total) and uses ports 1 and 2, and 3 and 4. On the motherboard edges, there are four extra sockets:

  • USB1314
  • USB1112
  • U31G1_78
  • U31G1_910

The first two are USB 2.0 (ports 13 and 14, and 11 and 12), whereas the other two are USB 3.1 (ports 7 and 8, and 9 and 10). These require a cable to be plugged into them, in order for them to work - I'm using the first two for RGB and fan controllers, and the last one for the sockets panel on the top of the PC case.

Port 11 is actually hosting a USB 2.0 hub, which provides a further 4 ports, but this isn't used by the device that I have connected to it.

If you want to know what USB speeds a port offers, use this free program: