Originally Posted by Sora1421
You are overthinking the whole thing and unless you want to get into the specifics of electrical engineering I suggest you ensure that your system is stable after a minimum of 12 hours in Prime95 first as TwoCables suggests. The more agreed upon time was always 24 hours straight in the past but many would only do 12 and not have real problems. A lot of weird problems can happen when you overclock something too high. After all, we are directly changing frequencies from what they were designed for initially.
The chip most likely simply can't handle those clocks at the current frequency without more juice. 70c is already about the maximum you want to allow this generation to go. Boot loops are generally the computer telling you that your BCLK is too high with the current Vcore.
Prime95's effectiveness as a test of your computer's stability can't be judged by the length of time it runs. This is because it's not applying a constant unchanging loads. Instead, it is doing something far superior to that: it is running through 82 different "FFTs", and you definitely want to make it through all 82 at least once if you're going to overclock this high.
With the latest version of Prime95, the length of time it should take to get through all 82 without changing the time per FFT would be less than 12 hours, but I don't know the exact average because I haven't tested it yet. If I were to make a guess, then it would be about 6-8 hours. You'd have to watch for the first bunch of FFTs to show up again to know when you can stop the test.
As far as the temperature is concerned, it's safe to exceed 70°C. I think the Tj. Max is 90°C to 95°C, and that's when the CPU would throttle itself down to reduce the heat - as a first line of defense. Failing that, the CPU could eventually just turn off to protect itself.