That voltage is barely safe, though it is indeed safe. I wouldn't go any higher than 1.35 and even that is very high. Is it really running 24/7, because if it is, that chip wont live very long
If it were my system, I wouldn't push the volts any further, but that's just me being carefull. Its your call, but remember that more volts means less lifetime.
70C under stress testing? I take it this is delidded then? Yea I wouldn't push any higher if I were you for an everyday CPU if you are planning on keeping it for an extended period of time
thanks the processor isn't running at 4.7 all the time too, i still have C-State, Speedstep etc enabled so it clocks back down and dials the vCore back when it's not doing anything intensive. so should still have a nice long life