Hi guys,
Sorry if this ends up a totally noob question, but I just can grasp what's going on.
I started using Claymore's miner 10.0, mining only ethereum on ethermine.org.

The machine has 3x rx570 4gb and 1x rx470 4gb.

Everything was going fine, and it actually increased my average hashrate from 67Mh to 78Mh (reported around 83)

But then, all of a sudden, after 3 or 4 days of great use, the thing started lagging substantially. To the point of dropping connection and verry chopy hashrate chart in ethermine. A few times, I even had to hard reset the rig, because I couldn't access it via teamviewer. I tried mining with -ethi 4, and it kind of works, but hashrate is shit, and it still isn't no where near as stable as before on standard ethi setting.

What can I do to get my hashrates back?