bump the cpu multiplier one tick at a time. When it stops booting windows go back a notch and test prime95. If that fails go back another notch until it passes.
It takes 1.312V to get to 3.9Ghz. I tried changing the ratio to 42 and voltage to 1.2. Could barely do anything. Even crashed whenh I did 1.25V. Why does 3.9 take 1.3???