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Comment by 55873445216111 | Hacker News Reader

I'm using a 5950X, and in the BIOS there is a setting where you can enter the power limit in Watts. So while the "X" CPUs consume more power as configured out-of-the-box, you can still set your own limit as desired.

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I have a 3200G and I limit it to 35W(of 3 built-in values, 64, 45 and 35) since I run it off a picoPSU. Haven't done much testing without the power limits, but it's plenty peppy at 35W.

These lower power limits reduce performance a lot on chiplet CPUs (unlike your monolithic APU). The impact is maybe a little less crass on Zen 4 because the 7nm IOD seems to use less power than the old 12nm one used in Zen 2/3.

For example, a 5600X in CB R20

   PPT   Freq      Points (nT)  Core power
   82 W  4500 MHz  4350         54 W         (stock)
   65 W  4200 MHz  4000         43 W
   38 W  2500 MHz  2400         17 W         (lowest allowed)

The SoC/uncore consumes around 15-20 W on Zen 2/3, so at 38 W you only leave 15-20 W for the actual CPU part of the CPU. Meanwhile the low-load and idle savings are essentially nil because all of the idle power is the IOD/uncore.

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