[OPENELEC] Problems with HD Audio (cracks, pops)

I'm using an E350 mobo with an nvidia gt610 in it, running openelec latest beta 5, all outputs are set correctly.

I get no DTS-HD when there is any kind of refresh rate setting on. Turning them off will get me a bit of HD sound but through the GT610 but it rumbles and crackles constantly, sometimes with a digital "squish" noise. Anyone have any suggestions as I am tearing my hair out.