kapgowild,
On behalf of Tom's Moderator Team, welcome aboard!
Sorry no one has replied to your thread. That's a bit unusual for our forums.
Your i5-6600K is a 14 nanometer processor, for which the maximum
recommended Core voltage is 1.4. It's predecessor, the i5-4690K is a 22 nanometer processor, for which the maximum
recommended Core voltage is 1.3.
Here's the maximum
recommended Core voltage per microarchitecture from 14 to 65 nanometers since 2006:
As you can see, one size does not fit all, but instead corresponds to microarchitecture and processor generation.
• Which version of Prime95?
• Which torture test?
• At what ambient temperature?
Although "Throttle" temperature for the i5-6600K is 100°C, it’s not advisable to run your CPU near its thermal limit. The consensus among well informed and highly experienced system builders, reviewers and overclockers, is that cooler is better for ultimate stability, performance and longevity. Experts all agree that it's prudent to observe a reasonable thermal margin below Throttle temperature.
Here's the nominal operating range for Core temperature:
Core temperatures above 85°C are not recommended.
Core temperatures below 80°C are ideal.
Core temperatures increase and decrease with ambient temperature. The "standard" for normal ambient (room) temperature is 22°C or 72°F. Ambient temperature is a reference point for Intel's thermal specifications, so in order to make an apples-to-apples comparison, it's important to state your ambient temperature.
Overclocking is always limited by two factors; voltage and temperature. No two processors are identical; each is unique in voltage tolerance, thermal behavior and overclocking potential. Without knowing your ambient temperature, at a glance it appears that you have voltage and thermal headroom to run your overclock up to 4.8GHz. Just don't exceed 1.4 Vcore and 85°C.
You might want to read this:
Intel Temperature Guide -
https://forums.tomshardware.com/threads/intel-temperature-guide.1488337/
Once again, welcome aboard!
CT