16.04 using llvm instead of graphics card

Question

lspci | grep -E 'VGA|Display'

shows that it has found my graphics card which is in the supported list and works fine on windows:

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Pitcairn PRO [Radeon HD 7850 / R7 265 / R9 270 1024SP]

dmesg doesn't show any errors.

glxinfo | grep OpenGL

shows that it is not using the GPU:

OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.8, 256 bits)

Is there any way to force Ubuntu to use the GPU as I am currently unable to watch youtube and run phpstorm at the same time without considerable lag.

Answer 1

The issue seems to be resolved after re-installing xorg.

glxinfo now shows

OpenGL renderer string: Gallium 0.4 on AMD PITCAIRN (DRM 3.16.0 / 4.4.0-96-generic, LLVM 4.0.0)

Compiz now isn't eating 35 to 50% of my cpu anymore.