S2340T Audio Problems

I am in a pickle. My setup is an old Radeon 5800 series, a win 8 machine, and the S2340T is plugged to the pc by the USB upstream cable and either:
1. HDMI, when set to this mode the monitor gives me sound but I am having rezising issues with the display being smaller than the actual screen margins which mars the touch functionality. I know I am not the only one, seems to be a bit of an issue for a lot of people.
2. DisplayPort,  no issues with screen resizing but no sound! As far as I know the DP option should be able to carry sound too.

If I unplug the HDMI and DP cables then I get the upstream USB cable to deliver the video and sound so, that would be good you would think but the mouse is laggy as <profanity> so, no go. If I could have the DP cable working sound and video I'd be in great shape.

Does anyone have a suggestion?

Thanks.