These 3 ports should be for your USB front panel headers. Usually its labelled on the motherboard USB_0 USB_1 USB_2 next to each one.
EDIT: Ooops ive just re-read and you said USB 3.0, picture might not be helpful. The Extreme3 Gen3 doesn't actually support front panel USB 3.0 - Extreme4 or higher is needed.
These 3 ports should be for your USB front panel headers. Usually its labelled on the motherboard USB_0 USB_1 USB_2 next to each one.
EDIT: Ooops ive just re-read and you said USB 3.0, picture might not be helpful. The Extreme3 Gen3 doesn't actually support front panel USB 3.0 - Extreme4 or higher is needed.
These 3 ports should be for your USB front panel headers. Usually its labelled on the motherboard USB_0 USB_1 USB_2 next to each one.
EDIT: Ooops ive just re-read and you said USB 3.0, picture might not be helpful. The Extreme3 Gen3 doesn't actually support front panel USB 3.0 - Extreme4 or higher is needed.
See this link for ASRock motherboard features http://www.asrock.com/microsite/IntelZ68/index.asp?c=Models
Yeah, guess that's why i was sitting there trying to find a spot for it for a while lol.