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Comment by rienko | Hacker News Reader

the cpu is certified by AMD to be running up to 105 celsius, but it thermal throttles automatically at 95 celsius, so out of the box probably not enough to boil water, but just barely :P.

the fun fact, is that if you manually reduce the power limit to 65W the initial single thread results so virtually no loss in ST performance vs 170W, and it appears that the original AMD slides stating 75% more efficient cores at that level not too far off.

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The previous generation of Intel and AMD CPUs could not consume more than 20 to 30 W with a single active core (non-overclocked).

So with the power limit set to 65 W or more the single-thread performance was always limited by the maximum turbo frequency (which may depend on the temperature of the CPU) and never by the power limit.

I have not seen yet any published value about the single core power consumption of Zen 4, but it is likely that the single core power is not higher. It is certainly much less than 65 W even at 5.85 GHz.

So the expected behavior is that the single-thread performance does not depend on whether you set in BIOS the steady-state power limit to 170 W, 105 W or 65 W. Only the multi-threaded performance is modified by the power limit, because when the power limit is reached, the clock frequency is decreased until the power consumption matches the limit.

Note that anyone trying to boil a kettle with a 170 W heater would be waiting around for 10s of minutes.

That's the consumer variants; the Threadrippers will almost certainly not be at a lower rated TDP than current gen's 280W. If they increased it by same percentage as they did for consumer, it'd be 450W, but that's unlikely; 350W might be in the cards, though.

Although if you just want to make hot drinks, then you probably don’t need 100c anyway, kettles just use that as an easy off switch.

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