Ok, I've been out of the inner construction of computers for a few years but it sounds like there is a dedicated sound card/processor for the HDMI that the game is running on and then the computer just generally runs off an onboard sound processor. You'd have to re-assign the processes to switch to the HDMI's dedicated processor. I don't know that it can handle that, but I don't know that it can't. I have no clue how to do that but is you google it the computer jargon you'll probably get something.