My audio solution for my home PC is an Asus Xonar STU, USB dac/amp. Out of curiosity I connected it to my Surface and installed the latest Win 8.1 drivers. No problems with install and the Surface device manager shows the Xonar is connected and working. Unfortunately I'm getting no sound when the Xonar is set as playback device. Also when I play a video/audio file I'm getting lag. Video lag is 1 or 2 fps with no frame skipping, like the processor is having a hard time. Audio is the same, witnessed by observing wave output and time remaining (using winamp). It's like its playing, albeit VERY slowly and without sound. When switching back to default speakers everything is normal. Suggestions?