Blender acting strange when rendering with AMD GPU

Hello all!

I’m using Blender 2.76, and i have aproblem with AMD GPU rendering. Basically when I want to render with multiple samples, I’m gettin a darker/greener image with every sample I add. However Progressive Refine solves the problem but it’s slows it down as hell.
I’m using AMD Radeon HD 7770. With CPU, and with my nvidia powered notebook theese settings are fine.
Tried searching other threads, various google links, and found no answer.

Thank you in anticipation.

Example:

1 Sample:



20 Samples:


80 Samples: