I've purchased a new Dell inspiron 7559 with an i7 6700HQ processor, 16GB ram and also with a 4k display at the dell retail outlet. There are several problems occurring with this device right now.
First thing is the Windows animations, the operating system that is provided with this device is a Windows 10 home version and the windows animations on this device ***. If the scaling of the screen is reduced to 1080p then the animations workout pretty decent and I've used other branded devices featuring a 4k screen and the animations on that devices work normally, if the problem is with the 4k display then why did they launch this device featuring a 4k screen?
The Second thing is the Touch Pad, occasionally the Touch pad doesn't respond to the input and points where ever it likes and the cursor takes a free tour all over the screen.
The Third one is the Screen Brightness, when I reduce or increase the Brightness with the function keys, after the level which I fix, the brightness automatically adjusts either by going up or down the level from the level which I've fixed.
I've contacted the Dell Tech support team, that was of no use, But how the *** even they can solve the problems which is with the mismatch of the build specs of the laptop?
The Dell Software Team should release an Update of the Windows 10 rectifying just even the animation problems with this device.
I would suggest you to check if the issue with the 4K resolution is same on different 4K picture or 4K video.
Also, connect an external 4K Display to the laptop to check if issue reoccurs.
Consider uninstalling the touchpad listed under 'Mice and other pointing devices in the device manager.
In addition, please use the link to disable the adaptive brightness using the link below.