Device Connect/Disconnect Issues with ASRock Z87 Extreme 6

I just built my new PC over the weekend and I thought it was running like a champ. At least until I plugged in my speakers. I am getting connect/disconnect errors on the motherboard. First my rig.

i5- 4670K
Asrock Z87 Extreme 6
8 GB Kingston DDR3 Ram
500 GB SSD
2 TB Hard Drive
MSI GTX 760
950 Watt Power and Cooling Haswell cert PSU
LG Blu Ray Player
Rosewill Blackhawk Case

So I put it all together, ran prime 95 for 12 hours, had no problems.

Then I plugged it into speakers and downloaded a couple games and I've discovered that some divice keeps connecting and disconnecting. The only thing I had plugged in was a keyboard and mouse. I've tried two different mice and two different keyboards. Dells and Logitechs.

I first noticed it in earnest when I was playing world of tanks. After about a minute into the game it picks up in frequency. every few seconds, the device disconnect, connect chime. Oddly enough, when I first boot up, it may only occur once or twice. Only after I start playing a game does it happen more frequently. Then, even after I stop playing it continues.

So I started troubleshooting. I've found that of my two rear USB 2.0 connectors, one isn't working quite right. For example, I can plug a mouse and keyboard into it, and they work, but when I look at the device manager, they don't show up. That's the back USB2_0 they don't pop up. That is the only USB plug that does this. Oddly enough, when I use the asrock hardware tool, it detects a dell usb keyboard. And the keyboard works. It just doesn't show up in my devices under devices and printers. All other USB ports appear to work normally.

So then I thought the problem was with my USB 2.0 port. But I found that the problem goes away ONLY when I disable my USB 3.0 Hub. Not my 2.0 hub. If I disable my 3.0 hub in device manager, the problem is gone.

I've tried reinstalling the Intel USB drivers. I've gone into the bios and changed the USB 3.0 setting sfrom amart auto to auto to enabled and none of that worked. I've changed from legacy to UEFI and that didn't work. My next step is to unplug and plug stuff back in.

I'm stating to think I need to RMA the motherboard. I've discovered there's something wrong with one usb 2.0 port and the 3.0 hub seems at the root of my connect/disconnect issue. But I'm stumped why it becomes worse when I play a game. The problem really comes pronounced when I play a game. And then it subsides several minutes after I'm done. And I don't know what could be disconnecting because all I have is the keyboard and usb. The chimes continue even when I unplug both.

Any advice before I have to tear the whole thing apart or RMA the mobo?

Update: I've updated the bios, unplugged the usb connectors from my case, and checked that all the drivers are updated.

As I said earlier, if I disable the USB 3.0 hub the problem goes away.

But I also found out if I remove the video card, and use the intel graphics with the i5-4670, the problem also goes away. I've tried two different nvidia cards. a GTX 760 and a gtx 650 TI Boost and the problem happens when both cards are in the system. I used a power supply tester to test my leads and the tester said I was getting good voltage.

I was thinking it could be a driver conflict with nvidia drivers but I've looked in event viewer and in the device manager and I still can't figure out if there's anything conflicting.

Has anyone had an issue with a z87 extreme 6 ASrock board and nivida cards? Considering I have an issue with one usb port and it doesn't matter wich nvidia board I put in, I'm still thinking I have a problem with my motherboard. Probably going to take the whole thing apart tonight and RMA is unless anyone else has some advice.