My specs are as follows :
Intel i7 PC
ATI R9-295x2 powering a 65" Panasonic Vierra 4k TV via DisplayPort 1.2 in 4096x2160
When I had upgraded to the latest drivers I noticed a problem.
When display would shut off (either by windows power setting, by me powering off the TV, or switching sources) reverting back to displayport which was used by windows would show a "No Signal" message on my screen.
The only solution to getting my windows display working again was to reboot my machine.
This happened EVERY time the displayport source was cut off. (almost as if there was no keep alive signal going back to the TV)
I uninstalled all ATI software and was using windows native drivers - problems were gone and my display was fully functional again. I could turn the display off, switch sources, and when going back to displayport I would be able to see my windows desktop.
I proceeded to install my previous version of ATI (ATI Catalyst Omega 14.12) and it has been working fine ever since.
My setup is not conventional, but I'm sure someone, somewhere may have a similar setup and will run into the same problem.
This problem is entirely driver related. More testing should have been done before release.
Just an FYI for anyone who runs into the same problem.