cause intermittent (every 2 secs) freezes/lags playing Zack Zero with i7-840QM and AMD 7970M 2GB, Windows 10 x64, 1080p 60Hz. It's impossible to play.
A friend of mine was not able to reproduce it on AMD 290x though, so it might be a specific driver issue with AMD mobile cards (runs fine on nVidia 980M).
Old drivers Catalyst 15.11.1beta + 7970M have no issues with Zack Zero.
- this game uses OpenGL2.1
- it happen only when in fullscreen. In window the lags disappear
- when in the Options menu the GPU is downclocked to 350Mhz GPU clock with slugghish effects. In game it uses correct speed 1200/850MHz