The Intel DZ77GA-70K motherboard has 16 USB ports (external and internal ports combined) listed in the user manual as follows:
• Eight USB 3.0 ports:
Four ports are implemented with stacked back panel connectors (blue)
Four ports are implemented through two dual-port internal connectors (blue)
• Eight USB 2.0 ports:
Four ports are implemented with stacked back panel connectors (two black and two orange high current charging ports)
Four front panel ports are implemented through two dual-port internal headers
However, on the actual motherboard, there are 5 internal connectors/headers, instead of the expected 4:
2 x Front panel USB 3.0 connector (blue) (labeled MM and NN in the user manual diagram)
2 x Front panel USB 2.0 headers (black) (labeled II in the user manual diagram)
Also, there is:
1 x Front panel USB 2.0 connector (orange high current charging) (labeled KK in the user manual diagram)
For the "extra" INTERNAL Front panel USB 2.0 connector (orange high current charging) connector/header:
1) Is this an undocumented 17th USB Port (where the specs say there are only 16 ports)? Or am I not understanding the purpose/usage of this port properly?
2) Does this port provide BOTH data and power? Or only power?
3) Is this port independent, or is it shared with any of the other USB 2.0 internal headers? (Meaning, there are only 16 USB ports total, but I can only use ONE of the orange OR black internal USB headers at the same time).
There are (obviously) some boo-boos in the GA board's TPS...
The Z77 chipset provides ten USB 2.0 ports and four USB 3.0 ports. These USB 2.0 ports are consumed as follows:
The GA board also utilizes two 4-port USB 3.0 hub ICs. This supports the four front panel USB 3.0 ports (the two blue connectors) and the four back panel USB 3.0 ports.
[Aside: Ok, you just did the math and you see a discrepancy. The hubs each consume one of the chipset's USB 3.0 ports. That means that there should have been a total of ten USB 3.0 ports available (two from the chipset and eight from the hubs). In fact, however, only three of the ports from each hub are actually utilized.]
Bottom line, you have ten USB 2.0 ports and eight USB 3.0 ports. Black USB 2.0 ports provide 500mA of power to devices, blue USB 3.0 ports provide 900mA of power to devices and yellow USB 2.0 charging ports provide 1500mA of power top devices - and yes, they all support data and they are all independent.