Is it normal to get GPU Usage like that? This happens to all my rigs. (5 of them)
That happens when the server changes coins? Or is it not normal?

What is happening is it is switching coins during those dips. Those dips are when there is no work from the pool. Hope that helps.

Tip: Add a backup pool (non-clevermining) so you don't loose out on hash time during coin switches.
This doesn't look like coin switches which are done without interruption.
For backup pools: I recommend setting another CleverMining regions as your backup pools.
Thats weird if its not the coins changing. What could be the problem? When it happens, its for 5-10 seconds each time.
I am using MultiMiner to monitor my rigs which are in another network and although I have a back up pool, it doesnt report as the eu pool being down. So it does not change pool.