We just got our hands on a retail unit of the Xperia Z5 Premium, but before we started our review routine, we spent some time marveling its 4K screen. Marveling quickly turned into examining and before you know it, we set out on a mission to find out whether we would readily spot the difference to other 5.5-inch smartphones with lower resolution.
Source: http://www.gsmarena.com/xperia_z5_premium_screen_test-review-1342.php