I have Kubuntu 16.04, so radeon driver only, my old graphics card is working fine, but my new r9 270 doesn't boot. The monitor turns on, then turns off, then turns on but there is only black screen. When I boot in safe mode I have no stable opengl support, onlty xrender, and for some reason youtube videos have only sound, I have yest to see if it's all html5 players
Plenty of AMD graphics drivers, including R9 270s, will not work with Ubuntu 16.04 LTS - I have an AMD A10-7700K Radeon R7 graphics driver, and Ubuntu 16.04 LTS does not work. I booted from DVD and pressed Try Ubuntu Without Installing and my monitor blacked out. I did a clean install of Ubuntu 14.04 LTS and everything is working perfectly fine. I highly recommend going with 14.04 LTS and not 16.04 LTS.
EDIT: By the way, Kubuntu 16.04 and Ubuntu 16.04 are the same thing, except Kubuntu uses the KDE desktop environment. If Ubuntu 16.04 will not work with most AMD graphic drivers, then Kubuntu will not work with them either.