RX 480 core clocks constantly fluctuating on idle?

I've just got a new RX 480, MSI gaming X version and on idle the core clock is constantly fluctuating like crazy from 800-1300mhz with the temps at 50 degrees ( I know the MSI cards fans don't come on till 60 ). Should this be happening?

Here's a screenshot.

http://i.imgur.com/TrPJePI.gif