Power cords have worked on everything I've tried them on, and that's a lot of stuff! They don't seem to make quite as big a difference with video as audio, although bear in mind those two are so very different its impossible really to equate. I think a better way of comparing with video is with things like a power cord vs something like Synergistic Research ECT. Just one of those alone makes at least as big a difference as a pretty darn good power cord. (That costs a lot more.) But if you mean sound then yes you should hear as much improvement as using it on any amp, preamp, processor, CDP, etc.
I do think the higher resolution, both source and monitor, the easier it is to see. When I compared ECT with really good source material my wife said right away Wow what did you do?! The image became much more natural and almost 3D. Like greater detail and contrast but without that hard edgy look high contrast detail tends to have. Colors, not really more vivid but with smoother more natural and wider range of hues. Pretty amazing for just one ECT! But the same setup with lower res material was hard to see any difference at all.
I do think the higher resolution, both source and monitor, the easier it is to see. When I compared ECT with really good source material my wife said right away Wow what did you do?! The image became much more natural and almost 3D. Like greater detail and contrast but without that hard edgy look high contrast detail tends to have. Colors, not really more vivid but with smoother more natural and wider range of hues. Pretty amazing for just one ECT! But the same setup with lower res material was hard to see any difference at all.