I am having a very similar issue with a Lenovo y40 which also has switchable graphics, though here it's an Intel 4400 and an AMD R9 M275X. I upgraded to the newest drivers and the problem actually got worse (trying to run Fullscreen results in a black screen requiring a hard reset). I rolled back to the Catalyst Mobility Beta drivers from November 2014 and now the situation has "improved" to where when I try to run Fullscreen, I get a window the size of the screen but with a border (as opposed to the borderless Windowed Fullscreen option).
Anybody seen this? Like others here, I don't have scaling options in my AMD control center, they are all in the Intel settings (or if they are in the AMD settings I can't find them).
