I just bought a Retina 4K 21" iMac from a friend. One thing I noticed is that colors are much brighter and more saturated on Google Chrome vs. Safari (an easy way to see the difference is to just look at the Google home-page. The red letters in the word "Google" are noticeably brighter on Chrome). Why is this? I never noticed this on the rMBP I had. This must be something to do with the P3 color gamut, right? Is this a known Chrome issue? Just wondering. The two browsers even handle this banding test differently: http://www.lagom.nl/lcd-test/gradient.php and probably some of the other tests on that site.