yes, at 7nm and below you pretty much have to have runtime monitoring of the voltage/temperature microclimate across each core (CU or SMX) because it simply is

yes, at 7nm and below you pretty much have to have runtime monitoring of the voltage/temperature microclimate across each core (CU or SMX) because it simply is not possible to validate that a given core will always be stable under a given operating regime. it is not possible to guarantee that the worst-case scenario of a very hot transistor (needs more power) that is in an area where voltage is drooping low and all the nearby transistors fire at once in a worst-case neighbor load will not result in switching times that are too slow and an incorrect output. the operating margin at 7nm and below is extremely slim and you just cannot get competitive clocks while guaranteeing that transistors will never be pushed out of their stability regime. And in computing, one in a million chance happens 1000 times a second. instead you actually design the chips to detect this and slow themselves down... that was the whole thing with "clock stretching" showing up on zen2. everyone has had to implement something similar, the chip watches itself and will either delay instructions or slow down clocks or something similar if the voltage/temperature is not going to allow the timing hotpath to converge inside the clock window. side effect is that now everyone is looking at "hotspots", but hotspots generally are significantly higher than the average, that's why you have to watch them. there is a much stronger "microclimate" where voltage can droop and temperatures can increase significantly between different regions of the chip. https://semiengineering.com/power-delivery-affecting-performance-at-7nm/ https://semiengineering.com/power-delivery-affecting-perform... also just very simply the density has been increasing faster than the power consumption has been decreasing (no more Dennard scaling) so overall the power (and thermal) density has been getting higher every time you shrink.