I think you may have a misunderstanding of how CPU’s act in terms of power draw & utilization, and what a CPU stress test is supposed to do.
Wouldn’t a real stress test increase the demand on the CPU until it at least reached its max temperature and started throttling?
The test just continuously performs specifically constructed operations that are designed to cause a worst-case scenario in terms of heat output. A stress test cant just keep increasing demand on a CPU until it reaches a temperature. The heat output of a CPU is proportional to the amount of power it’s drawing. The power draw is limited by the motherboard in order to prevent damage to the CPU and its supporting circuitry, such as the voltage regulation modules who tend to get pretty toasty under load. Some motherboards let you adjust these limits for extreme overclocking with special cooling systems.
That being said, Precision boost overdrive isn’t going to infinitely keep boosting the core clock (and power draw) up and up until it reaches 95c either. It’s programmed to have a max boost clock that it can’t exceed no matter the core temp of the CPU.
If the cooler can dissipate more heat during the test than the CPU can output while Precision Boost Overdrive is boosting to its max clock speed limit, you’ll get the situation that Jay has in his video. Sticking to the max boost clock with temps below the limit.
My guess would be you’re not getting good contact between the cooler and your CPU. Or the paste has some issues. One way to tell would be to feel the air that’s coming out the sides of the CPU cooler while the CPU is at 95c. Just be careful not to get your fingers in the fans, or touch the potentially very hot heatsink. The air wont hurt, but the heatsink might. If the CPU is at 95c and the air coming out the sides of the cooler is not at least quite warm, then the issue is likely bad thermal conduction between the CPU and the cooler.
If the air IS quite warm, then I would guess either hot air is being fed into the cooler, or the cooler just isn’t able to dissipate enough heat to keep your CPU below the 95c limit at max boost clock and you may want to upgrade it. Hope this helps.