virtualbox.org

F21 64 host
Win7 64 guest
Bus 001 Device 004: ID 0c45:648d Microdia

I've given up, for now, on using web cameras/webcam, as it only gives me a black screen, so I try to use usb devices/webcam. When I do that, it works, but it slows down the guest so severely that it is unusable.

Any way to resolve this?

Did you install the guest additions in your Win7 guest and are 2D and 3D enabled for the guest?

Yes, still incredibly slow webcam. If I do passthrough, I only get black screen film webcam.