yes! i also get it even without mouse and keyboard and even without ANY usb plugged i also found this i hope it helps even more
im now sure that its The Universal Bus Controller's fault..but how i fix it first time countering this....
Project Name: System Specs:
Motherboard: Asus Rampage IV Black Edition
Prossesor: Intel Core i7 4820k
Graphic Card: Asus GTX Titan x2
*Power Supply: Cooler Master V850
Ram: 32Gb Corsair Dominator Platinum 2133Mhz
Case: Corsair Obsidian 750D
SSD: 2x Samsung Evo 250Gb Raid 0
HDD: 2x Seagate Baraccuda 2TB