Strange Issues with Win 8/8.1 & Unity

Having some difficulty trying to track down the source of some strange issues that seem to only affect users running our Unity game on windows 8/8.1, and would appreciate if anyone here has any experience with these issues/thoughts on how to solve.

In short, the symptoms seem to be as follows:

1) Usually within a few minutes of starting, Players seem to have their Razer Hydra stop responding/intermittently respond. The same thing seems to happen with headtracking on the Oculus Rift (headtracking through USB connection), but one doesn't seem to affect the other (ie they stop responding independently of each other). 2) We are able to reliably cause the Hydra to stop responding when exposing our various 'sets' in the game, suggesting the issue might have something to do with a spike in VRAM usage.

Trouble-shooting efforts to date: 1) Ruled out physical problem with Hydra/USB - everything works as intended when using the same Hydra and Rift on a non windows 8/8.1 system. 2) Found that win 8 has an advanced power management setting to 'selectively suspend' USB - disabled that feature but it did not solve the issue - later read some comment boards indicating that win 8 might override the manual disabling of this feature! 3) A ton of reading :)

If anyone has any thoughts on this, please let us know, would be much appreciated!