I updated my drivers to Crimson 17.2.1. Since then, every game that is played in (borderless) window has extremely unstable FPS/stutter where the game pauses every .3-.5 seconds. In fullscreen mode, this issue isn't present at all. Check this imgur album for the WattMan graphs of some games in different modes (no, I didn't touch any of the controls there). As long as the game window is unfocused, the FPS and the clock speed are stable. When it gets focused, the FPS and the clock speed are just all over the place. This seems to be a driver bug. My current workaround is to just play every game in fullscreen, but with my multi-monitor setup that's not comfortable and I'd like to resolve this issue. Thanks.
(Possibly irrelevant information, but whatever)