Regardless of how many colors or what resolutions an engine can render there is a limit to what the human eye can perceive. m739pd is correct, it would be very difficult for anyone to detect the difference between one shade and the next at even 24 bit color. Same as once the resolution gets below one minute of arc, your eye can't see it. At 24", roughly the typical distance to a screen, and a 16" screen, that occurs at about 3500 x 2600. Same with sound. There's not a person alive that can hear above 20 KHz, but we have sound systems that go up to 44 KHz. Fact is most people over 25 can't hear much above 12 KHz.
Part of the hype on colors and resolution and KHz is just that, hype.
Its like advertising a car can go 200 mph. Uh, so what, when or where are you going to get anywhere near that in normal usage. So for all pratical purposes, anything over about 150 hp is meaningless except for bragging rights. Same with SUVs, 95% of the owners have never been off road and if they did get off road, they'd get stuck almost immediately. There's more to off-road driving than 4WD or lots of power or high ground clearance.