It was visibly false with Monster cables, do you know anyone with a 1080p+4K monitor setup you can look at? The difference is really obvious with multi-monitor setups. Hell just try reading small text, it has to be way bigger on the 1080 before your eyes are straining to read it.
Also again, emulation, look really closely at a pixel on a CRT. Trying to copy the depth effects with 9 or fewer LCD pixels just isn't possible.