I'm too cheap to afford full water cooling.
I managed to get to 5.2Ghz stable with the 620.
But idle temps were 70 degrees so I was like fuck that.
So around 4.8Ghz, it went up to around 70~80 degrees on full load.
70-80 on full load still sounds pretty high... But it's ok
What Brand of Thermal Paste did you use?
Did you apply a thin Coat?
What case are you using?