I've recently installed elementary OS Freya 0.3 on an laptop, but it doesn't run as smooth as on my desktop PC. It's sluggish while opening windows and especially switching pages in the application menu. I think that it could be a problem related to drivers, so I've tried installing ATI drivers from the software center and even from the AMD website, but at the next reboot there is only a black screen. I've done all software updates and also tried installing the 3.19 kernel, but it boots to a black screen again. How can I solve this? Is there any compatible driver?
(CPU is an AMD APU A-micro 6400 T quad-core)