Full Native USB 2.0 support? Poor Performance

Discussion in 'Windows Virtual Machine' started by Jaina, Jul 18, 2007.

  1. Jaina

    Jaina Bit poster

    I having troubles getting my external DVD burner to work properly with a Windows XP SP2 in Parallels.

    Under OSX I can read/write DVDs in good speed, about 8x (whereas the drive could do >16x, but ok).

    When I connect the drive to parallels instead, using the CD/DVD-Rom menu I get about the same results, but in this case the drive is not actually connected over USB to parallels. It is connected as internal drive and OSX does the USB communication.

    When I connect it using the USB menu, read speed drops to 2x, writting even to 1x, as the buffer on the device is fluctuating and would run dry if the device would not slow down to 1x.
    If I dare to connect a USB hard disk to read an image to, read spead drops to 1x, too, the RAM buffer runs full and write performance to the hdd is not noticeable...

    So why don't I connect the drive using CD/DVD-Rom and all is fine?

    Cause both in OSX and windows I cannot write dual layer discs or use light scribe in this setting. When booting to boot camp both work flawlessly and I can even write DVDs at >12x speed, etc. This tells me that the drive on a windows machine works perfectly well and OSX just hasn't the right support for it or whatever.

    When I connect the drive to parallels over USB, I can also write dual layer discs, but that isn't really fun at 1x speed...

    So my conclusion it that I could use the drive to full potential on my MAC, if parallels USB support would be at 100%. It's either just a performance issue of the USB emulation or some incompatibility, I guess.

    I also bought parallels to be able to use this particular drive to full strength on OSX, knowing that the drive is officially unsupported by OSX. Now as it is I can just use some functionality of it in OSX and have to reboot to bootcamp anyways for the rest... If this doesn't change quickly I guess I will give vmware fusion a shot at it.

    Thanks in advance for any replies,

  2. Jaina

    Jaina Bit poster

    It appears that Apple has changed something in their USB support in 10.4.10. Maybe this is the source of all these troubles and parallels just has to adapt?

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