PLL is different to any of these settings. Leave it as auto for normal overclocking.
As for the settings, I made a mistake! Level 1 for LLC is the highest setting after some googling
So the fluctuations were actually Vdroop, not LLC kicking in.
Try level1 LLC and manual voltage.
I might say it right now, but don't bother overclocking over 4.5Ghz for a daily overclock. I mean if it's for fun, then sure, go for it. You will see minimal difference in real life after you go over 4.5GHz.
Another thing to note is that 50% of chips hit a wall at 4.7/4.8Ghz. So I guess you might have been unlucky to get a chip that isn't stable at 4.8 without going overboard with the voltage. I couldn't get my chip at 4.8Ghz without going over 1.42V, so I gave up.
So in the end if you can't get 4.8Ghz with level1 LLC and manual voltage, try for a 4.5Ghz or 4.7Ghz overclock.