Does the Crimson Relive Edition drivers (16.12.1 - present), that added Wattman for older cards crash for anyone else? I had to revert back to 16.11.5 because it was ridiculous how often it would crash. It doesn't play well with Afterburner either which I need for the custom fan curve since the Wattman only provides a basic Auto & Manual fan control for 290x (very pathetic).
They have made a couple updates because of known issues. May be one of them will fix yours? I still have the initial relive driver version, and since it doesn't cause any trouble what so ever to my 270X I'm not changing it. But really, try the updates. I think they have a brand new version with RE7 optimizations... You may want to try that as well...
I had a few issues with 16.12.1 and my 290x, then AMD rolled out 16.12.2 rather quickly which fixed most issues but overclocking and voltage controls on wattman are trash for the older cards.
And amd just released 17.1.1
I would suggest updating first but I wouldn't expect the greatest results with wattman