USB throughput extremely slow

Discussion in 'Windows Guest OS Discussion' started by TomL3, Aug 6, 2018.

  1. TomL3

    TomL3 Bit Poster

    I'm running a Windows 10 Home VM on a 2017 13" MBP (Touch Bar, 4 Thunderbolt 3 Ports). I use a few different applications that use a live view from a camera - in one case a Canon DSLR, the other a specialized webcam. Both use USB 2.0, which I connect via an Apple dongle to the Thunderbolt ports.

    What I am finding is that the live feeds from these cameras are coming in at an extremely slow rate - close to what I would expect over a USB 1.1 connection. I don't know how to measure the throughput directly but the frame rates I'm seeing indicate it's about 16 Mbit/sec.

    Using the same cameras and software with two different cables and a Windows mini PC, rates are 25-30 times faster at least, and I also tested the Canon with its Mac utility and the live frame rate was normal. This definitely isolates the issue to my Parallels Windows VM.

    Are there any known issues with USB throughput in Windows 10 on Parallels using current Macs? Is there a driver update that might help? I did note that all drivers claim to be current in my Windows VM. I did a forum search but "USB" is too short a term to search for.
  2. PaulChris@Parallels

    PaulChris@Parallels Product Expert Parallels Support

    Hi @TomL3, please connect the USB devices directly to the virtual machine to get faster access("Devices" from Mac menu bar -> External Devices -> USB ) and keep us posted the results.
  3. TomL3

    TomL3 Bit Poster

    Hi there, thanks for your patience as I was away for a few days.

    I had already been using the cameras as per your suggestion, connected directly to the VM. To my knowledge they won't work at all without that configuration. In any event I explicitly tried that again today and found both cameras were still affected in the same way, showing extremely slow frame rates. (One camera also shows some "stripes" in its feed - a corrupted image - that does not appear on any other Windows PC I use.)
  4. Baron1

    Baron1 Bit Poster

    Hi, I wonder if you ever got anywhere with this? I paid for an upgrade to version 14 largely to use a Canon DSLR for live image capture under Windows. Unfortunately I get no more than 1.3 FPS in any capture app where the same camera with the same software will gave 25-30 FPS natively under either OSX or Windows. The camera is connected to the VM via USB 3 on a MacBook Pro.

    Any ideas?
  5. KebhaK@Parallels

    KebhaK@Parallels Parallels Support

    Follow steps in this article and check the camera on Windows virtual machine.
  6. Elric

    Elric Parallels Developers

    The Parallels has ability to share Camera with Mac OS. It is enabled by default. Just don't connect the USB camera to VM. Windows should see the camera. Could you please try this?

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