>>302042105
According to https://old.reddit.com/r/oculus/comments/5s72ip/oculus_cv1_sensors_usb_power_usage/ and https://en.wikipedia.org/wiki/PCI_Express#Power , you'll probably be able to draw enough power through just the pci-e slot to power the headset and a sensor. More of a gamble though. https://forums.oculusvr.com/community/discussion/28973/usb-3-0-compatible-expansion-cards/p2 mentions the powered cards being recommended, but no details on the unpowered ones.