I just upgraded from a GeForce 550 Ti to a Radeon R7 370 and I'm struggling to get a setup that's faster in 3D but not buggy.
There's many options (fglrx, amdgpu/radeonsi, xserver-xorg-video-ati/radeon) and many things are rapidly changing.
I'm using XFCE in Ubuntu 14.04 - PC x64.
I tried fglrx-updates - it had better 3D performance than the 550 Ti, but I had terrible 2D glitches (minimized windows flickering, parts of window structure going invisible, stripes of garbage pixels appearing for a few ms).
I'm now using xserver-xorg-video-ati (the default open-source version) and getting framerates about 1/2 what I get with the 550 Ti. I need to boot with radeon.dpm=0 though (is this a significant problem?).
So, what's the current best setup for a R7 370 in Linux? Should I be using radeonsi?
also asked here
will update either if I get a good reply