Why am I having to fiddle with xHCI BIOS settings to run VR?

The Internal

Limp Gawd
Nov 14, 2004
Hey all.

Hoping someone with more computer science book learnin' can explain why my Rift keeps taking a dump on me. I'm doing room scale HMD + sensors, so 1 HDMI and 4 USB ports total (at least 3 USB 3.0 ports, ideally). Currently running into the issue on my Gigabyte Pheonix SLI x99 with my i7-6850k, 16 x 2 DDR4 3200 RAM, and the Asus ROG Geforce 1080 OC on a clean install of Win 10 Pro April 2018 edition.

I've been having issues with what I can only speculate is some issue between the motherboard BIOS, Windows, and the Oculus software. I'd previously had a defective HMD that had a warranty replacement... I think from a bad HMD cable.

If I leave xHCI enabled on my motherboard, Rift errors on a sensor every 5 to 10 minutes, kicking me out of any VR program running. I'm now having issues even if I do disable xHCI. If I leave xHCI on, I get tons of random USB drop outs (including knocking my mouse / keyboard combo out for 5-15 seconds at a time due to the USB dongle going out with the other stuff).

I've already disabled windows power management of every USB hub (3.0 or 2.0). Does anyone have any good idea as to why this happens? Another "fun" symptom... I'll hear the windows "disconnect" audio blip while in the headset, the image will stay on in the headset for a bit, but tracking completely stops... then, I assume, Oculus software flips it's shit and closes all the VR apps.

Any thoughts on why this is happening? Sounds like a not uncommon issue from forum posts I've seen since 2016.
Add on USB card for real!!
I had to do it on my x79. Now on x299 everything is supported. No Add in Card needed.