Remove any dust on the fans in all the computer, especially on the CPU. If its clean and still, high temp. Reapply thermal paste. Worst case, you need a better cooling fan on the cpu.
I run my pc on standard clocks for some years. Then I got high temp and pc shuts down. I then re applied thermal paste on the cpu and everything was in the green.
But if your computer run everthing perfect on 4.2. Just clock it down. But re apply paste just to be sure..