I have been surprised to find how little information there is out there about USB 3.0 ports, how they are powered, and the typical problems we all run into with them.
I have spent some time digging around the interweb and found a few tid bits of interest, as well as my own experiences:
So to do with the front panel headers on motherboards and adapter cards for USB 3.0 - the standard output for these connectors is limited to 500 mA, which paired with the front headers themselves being connected with long, high gauge, poorly shielded, and relatively poorly made cables makes a storm of bad communication and underpowered front ports, especially when trying to use fast devices like USB sticks and USB-powered external hard drives!
I myself have encountered poor write speeds on my USB sticks in the front USB 3.0 ports, and they periodically drop out, as well as serious drop outs or not even being able to read or power external HDDs that are powered through the USB cable. These problems never occur when I'm using the back ports directly off my mobo or adapter card, and going back to the power issue, this is because the USB ports on the mobo provide 900+ mA of power, and the front header ports are only given 500 mA of power (found this out through tech support for one of my cases).
Now all this being said, there are other factors at play as well. One big one is poorly shielded internal front panel cables which use high gauge wire and the length of the wire alone creates resistance which slows device communication down. This problem does not exist on the mobo ports because they are directly connected to the controller with no China made cables in the way to interfere.
Another issue commonly run into is drivers. If you have poor drivers or windows drivers they usually always slow things down or lead to the ports not working at all, so make sure if at all possible that you have the correct drivers for your system.
Lastly I have read of several instances where computer cases have had defective front panel USB 3.0 cables and/or ports/connectors leading to a plethora of issues such as drop outs, no communication and poor communication with devices leading to data corruption.
So in conclusion my advice would be to make sure your drivers are up to date and correct, and to really just avoid using the front USB 3.0 ports if at all possible, the rear ones are significantly more reliable and stable.
Good day everyone!
1+1. I'd like to know as well! – agirish – 2012-12-27T18:06:30.847
1a simple google search gave me this info - yes there is a difference! Mainly to to do with power. Hence it affects performance. The back ports have more power capability – agirish – 2012-12-27T18:10:24.540
and you are less likely to bump the computer and disconnect the plug when its on the back. for stuff like flashing a phone's rom over usb, it is always recommended you use back ports, both for power and stability. – Frank Thomas – 2013-12-02T13:01:49.247