AMD's automatic updater (not Windows Update) installed 15.30.1025.1001 for my R270 a week or two ago, and within two hours, the system froze completely three times. I rolled back the driver to 15.300.1025.0, and it kept happening. I have tried the "16.1 hotfix" release, with no success either.
The system works fine while it's doing anything, then freezes when nothing much is going on on the screen. As an example, it will play hour-long YouTube videos perfectly well, but when the video ends and the "autoplay next" clock appears, there is a better than even chance it will freeze before that countdown runs out. Similarly when I pause it for more than a minute or so. The mouse pointer will vanish, and that will be it, reset button to the rescue. This is not related to standby mode; I have already tried disabling that.
There are no artifacts on the screen, it is simply frozen. There is no unusual activity on the hard drive either (I'm not sure if there isn't any, it just isn't lit up continuously.)
When shutting down the system, it will hang instead of powering down, every time, very late in the process, after the monitor has already turned off.
This definitely all started at the same time the driver update happened, so I obviously suspect that it had something to do with it. Any chance the driver update also affected the firmware of the card itself, so the problem would persist even with the earlier driver?