I sent a similar message to support over the weekend but it is still in an unread state so thought I would try here too in the meantime.
I have just bought a pre-overclocked GA-Z77X-UD5H motherboard (F8 bios) with 16gb ram. Everything on it is great, EXCEPT that the USB 3.0 sockets don't work correctly. For mouse, keyboard, or file transfer under about 100mb they are fine, so most wouldn't notice it. But any USB device, such as a hard drive, USB stick, etc that I connect up to those 4 sockets won't work, it will either get to a quarter of the way through a transfer and then dramatically drop to slow broadband speeds of 200KB, or it will just cut out and the drive will vanish, the higher the MB or GB level the worse it is. If we are talking around the 100mb to 200mb mark, which is the smaller file size end of the problem, then it might get to 99% but then stall on that. But if I move a 5gb file it won't get further then 1/4 of the way through before the speeds drops to 200KB or cuts out.
I have tried EVERYTHING I can think of, except the latest motherboard bios, but I am reluctant to install that as it won't let me save my overclock profiles, it says there is no disk found when I try to save to USB stick in bios, even though it prints screen to the stick fine. I need to save the profiles as it was overclocked for me, and I won't be able to do it myself.
I have also tried to install Windows 8 as a test and found that suffered from the same problem, although for a moment I did get full speed on all sockets, but then when I reset it was back to not working again. So I know the sockets have the potential to work full speed, it must be a driver issue.
Copying internal HDD to internal HDD is fine, but copying anything to a USB 3.0 socket device doesn't work IF over about 100mb, smaller files do work. Here is what I have tried..........
1. I have tried 4 different SATA external hard drives in 2 docking stations. These work fine when connected up to my other PC so I can rule them out of being faulty.
2. I have tried a USB stick, same problem.
3. I have tried all sockets
4. I have tried a Gigabyte GA-USB 3.0 card just as a test, and the same happens, I am guessing this probably uses the same drivers (this card worked full speed in Windows 8)
5. I have formatted my SSD 4 times now and re-installed Windows 7 four times and same happens (make that 6 times since I wrote this first, and include windows 8)
6. I have tried both Windows 7 and Windows 7 Service Pack 1 and Windows 8
7. I have tried to copy files as soon as Windows is freshly installed with only USB drivers loaded, to try and cut down on any conflicts, the same happens
8. I have tried to go via a USB hub
9. I have turned off the option for energy saving to turn off hard drives, I have turned off the USB suspend option
10. I have tried other file copying software (such as Teracopy)
11. I have tried latest drivers from Gigabytes website (on some tests I formatted and installed with disc drivers, other tests I used website drivers)
12. As a test I disabled the HCI Pre-Boot Driver, and I found I got full speed on the USB 3.0 sockets when I saved and loaded Windows 7, but after a reboot it was back to not working. I briefly got full speed on Windows 8 too, but again on the next reboot it was back to crap
13. I have tried to disable xHCI streams
14. I have tried to install a hotfix which seemed to mention a similar problem, but it was only for nvidia motherboards so didn't work and wouldn't install
15. I have tested limiting my windows memory by using a command prompt command to 3.5gb in case my high memory was causing problems, this didn't help
Other items I have.............
RocketRaid 640 card that connects to 4 hard drives in RAID 5 mode.
Coolermaster 700watt PSU
AMD Radeon 6670 HD
LG DVD-RW USB
Pioneer BD-R internal
EDIT : I bought a USB 3.0 4 port card today and just tested it, that uses a PCI-E socket inside my PC. Known as the TeckNet USB 3.0 Card. I got this because it uses a different driver/chipset than the Nec USB 3.0 one in the Gigabyte. Thankfully this card works fine. So I have a workaround, but this is not ideal, I need to make those 4 USB 3.0 sockets on the motherboard work to their proper potential.
Thanks for any help.
