Not sure where how "long a cpu will last" entered the thread...I even agreed with you that the cpu is fine at 87.8c...as long as the OP is fine running near the base clock. He was specific about running a full load and the temps he was seeing reached 87.8c which is too hot imo due to the cpu clocking down towards or at base clock. This link provides insight -
https://www.gamersnexus.net/news-pc/3492-ryzen-cpu-thermals-matter-coolers-and-cases
The OP was asking about cpu temps not vrm's and didn't mention it as a potential problem area. As far as my system...mine are nice and cool at 50c running a 100% load.
Regarding boost freq I've run both the 2700x and 3600 under sustained 100% cpu load on water cooling and they do not hit anywhere near the boost frequency under an all core load. Im looking at my 3600 at 3.9ghz clock @67c across all cores right now on a 100% load as i type this...maybe I misunderstood you, but if you can get anywhere near boost clock speeds at 100% load please send me a PM as I don't want to hijack the OP's thread.
This is not jacking the OP's thread if its relevant to his question, which it is. He was concerned about temperatures and their effect on his CPU.
I have seen the test you linked. Throttling is NOT the cpu running at base clock as shown in that review. Throttling due to temperature is when the CPU is exceeding its thermal limits. a CPU base clocked at 3.8 ghz that is managing to boost nearly 4ghz across all cores at 84c is NOT throttling, even if that CPU is capable of faster speeds (under boost which is NOT continuous only temporary) if its cooler. Maybe this was a miscommunication between us, or a misunderstanding of terminology, but there is a massive difference between a CPU throttling to protect itself and a CPU not boosting due to thermal range. Hence telling the OP that his CPU is throttling to protect itself at 84c, is very much wrong, it is not. You are correct as in its not the CPU's maximum potential, but its not being handicapped either.
As for the VRM comment I was referring directly to you and your assertion that your CPUs are "taking a nose dive above 75c", because again, they aren't. The link you posted shows a variance in boost frequency of about 25mhz above and below 75c, thats hardly a "nose dive".
In the end the OP's CPU only managed these temps under a stress test unrealistic load. It never got anywhere near actual throttling temps which would be concerning over time, and in real life he has temperatures that keep it within the range for it to boost and operate properly, so he has nothing to worry about.
Regarding your final comment I agree, irrelevant to the OP so we can take it offline later.