Oh sorry misunderstood. Well, it's a little bit all over the place. Before overclocking, one TV I tried had 720p. It had occasional audio cut outs. Another TV had external speakers and had a resolution of 1920x1080. That one had terrible audio drop outs that lasted the longest. The last one I tried was at 3,840x2,160 and was working better than the other two. The audio dropouts were there but they didn't last as long.
Since that 720p TV still had audio drop outs, I don't think that could be the solution. But I haven't tried changing the resolution for any of the TVs so I'm not 100% sure.