3 Replies Latest reply: Nov 12, 2013 6:41 AM by Nexus6generation
Nexus6generation Level 1 (0 points)

Greetings folks,

I have a question for you.

If I connect one usb 3 device to one of the usb slots on macbook pro and one usb 2 hub into another, will that slow down usb 3 device? I have an external hdd usb 3 which I want to connect to macbook directly, and usb 2 hub which I want to use for couple of hardware devices. Will this setup slow down transfer from usb 3 HDD? Thanks!

MacBook Pro, OS X Mountain Lion (10.8.3)
  • OGELTHORPE Level 8 (45,045 points)

    Once you introduce a USB 2 device, the data transfer will be at USB 2 rates.



  • Michael Black Level 7 (20,382 points)

    According to Apple's FAQ (http://support.apple.com/kb/HT5172#7) and posts here, the important thing is the order that mixed devices are connected.


    If you plug in the USB2 device first, the entire bus will set to USB2 speeds.  However, if you plug in a USB3 device first, the bus sets to the superspeed bus (USB3 bus) and any USB2 devices are then limited by their own internal bandwidth not by the bus itself.


    You can always check in About This Mac's hardware report - look under the USB section and see if you have anything under the SuperSpeed bus, which is the USB3 dual-speed bus. USB 3 uses a dual-bus system that allows USB 3 traffic and USB 2 traffic to operate over the cabling simultaneously, but the first device will determine what the bus speed defaults to.

  • Nexus6generation Level 1 (0 points)

    Thanks, this pointed me towards the answer!