Retired my GTX750 and bought a Sapphire Nitro+ RX 480 4GB today and my problems started right away.
I have a Philips Cineos LCD-TV 47PFL9703D 47" http://download.p4c.philips.com/files/4/47pfl9703d_10/47pfl9703d_10_pss_swese.pdf
Your driver 16.12.1 won't recognize that my HD TV can handle up to 60Hz.
The driver identifys the HD TV as up to 50Hz compatible only and will not present a 60Hz option.
I tried the custom resolution and tried to create 1920x1080 @ 60Hz but the the driver says the HD TV is not compatible with this setting and won't proceed.
It seams that your custom settings are checking the drivers faulty monitor/tv identification for the faulty spec and will not continue with the custom setting.
Why is your custom resolution function not accepting this settings, isn't that why its called CUSTOM resolution and what it is for.
So i am now sitting with this RX 480 that cannot even perform the most basic function like setting 60Hz on a 60Hz comatible HD TV.
I can say that that i had no problems with GTX750, it properly identified up to 60Hz and i used 60Hz for years.
Expecting a swift fix for this most basic function, don't know how it is possible to let a bug like this exist in your drivers.
If there is not a fix for this within the next week i WILL RETURN RX 480 and buy an NVIDIA GTX 1060.
A note, your AMD REPORT ISSUE FORM is not working, when klicking on the link "www.amd.com/report" in the post it says redirecting to page and you just stuck and never go any where
Leave only one display for next operation
2.Install 16.12.1 Custom install>Clean install
3.Try previous WHQL 16.9.2 if you have no success with steps 1 and 2