cross-posted from: https://lemmy.ml/post/9114359

My motherboard provides 4x USB 3.2 Gen1 ports for rear I/O and another 2x USB 3.2 Gen1 ports for front I/O (through the header), but my chipset only supports 2x USB 3.2 Gen1 ports. Where is the support for the other ports coming from?

Motherboard Wikipedia
Motherboard rear I/O: 2x USB 2.0 ports, 4x USB 3.2 Gen1 ports, 2x USB 3.2 Gen2 portsMotherboard headers: 4x USB 2.0 ports, 2x USB 3.2 Gen1 ports Wikipedia B450 chipset: 6x USB 2.0 ports, 2x USB 3.2 Gen1 ports, 2x USB 3.2 Gen2 ports

The motherboard is an ASRock B450M Steel Legend

  • glibg10bOP
    2·
    11 months ago

    Likely SB

    Are you saying this motherboard likely has a southbridge?

    • Septimaeus@infosec.pub
      2·
      10 months ago

      lol yes, right next to the IDE connector. Nah I meant from the chipset. Here’s the doodle from my mainboard manual for example.

      aorus b650i chipset diagram

      • glibg10bOP
        2·
        11 months ago

        Ah, so the chipset uses a few PCIe lanes from the CPU for some USB controllers, and the other USB controllers use dedicated USB lanes coming from the CPU?

        • Septimaeus@infosec.pub
          3·
          11 months ago

          Right, the CPU has a number of standard I/O controllers onboard including USB. No PCIe lanes required for these IIRC. They live on the die itself, often adjacent to the PCIe controllers.