This is over-simplifying a bit ...but these chips are designed to use 90c as a target temperature, they will (within certain parameters) ramp voltage and clockspeed upto the point where the chip will hit 90c which is the thermal design 'limit' that the boost algorithm will work with. So as I said, this is oversimplifying it but it's a good way to think of it at least. Most people can't realistically cool one of these chips to the point where it will still hit it's maximum performance at a lower temperature than 90c unless you start to play with the Curve Optimizer to alter the boost algorithm and TDC limits this way, even a 360MM AIO is going to see the chip hit 90c, it's just that it will do this at a sustained higher clockspeed than most aircoolers will. On a 280mm AIO I have tuned mine to sustain maximum clockspeed at around 82-84c ...I can actually allow it to boost higher than 4.8Ghz if I want to by using the remaining temperature 'allowance' if you will, this is what Curve Optimizer is for.
You really do have to change the way you think about CPU temperature somewhat with these chips.
Sort of yes and no.
The is a limit, that limit is 4.85Ghz on the 5800X, its 4.95Ghz on the 5900X and 5.05Ghz on the 5950X, other than core count its how AMD segment these CPU's.
The Curve optimiser doesn't have any effect on ST boosts because there isn't a cooler bad enough to thermal throttle a single core, but when you're running all 16 threads at 100% load eveything changes, the maximum volts you see are around 1.35v, in ST workloads its around 1.5v.
Even with temperatures under 90c, and yes actually i'm running between 75c and 80c at 100% 16 thread loads i'm still only boosting to 4.7Ghz, sometimes slightly more, 50Mhz or so... My PPT is around 100 to 110 Watts, with 142 available, so its not hitting the temperature limit, its no where near the socket power limit. and yet i'm still short of the maximum boost range.
So what is it? its the third aspect, its not going to pump 1.5v in to all 8 cores all at once even when it has the thermal and power range to do so, because doing that would probably burn the chip out prematurely.
what its actually doing is very clever, it has its thermal limits and its power limits, but, and this is an actual explanation of how this works, the CPU is monitoring its own stress load from one millisecond to the next (No BS actual time) and it knows how many volts and mhz it can push the CPU depending on how high the stress is on the CPU.
As it happens i have a Negative curve set to 7 and +150Mhz, that's a maximum boost of 5Ghz, with 100% load i get to around 4.7Ghz to 4.8Ghz, ST 5Ghz, but in games, even games that have all 16 threads loaded to some extent i get 5Ghz, sometimes dipping 50Mhz or so, and the volts in that situation are around 1.4 to 1.5v, a game, even a very stressful game is not that stressful so it will allow the CPU to draw more volts and high Mhz.
Zen 3 is possibly the first Smart CPU, it thinks for its self what's best for it.
