The X570 chipset is strange. It's just a Zen 2 IO die backported to GlobalFoundries 14nm. Presumably they were able to remove the unnecessary parts (memory controller) while backporting, but maybe they're reusing excess chips if they chose late in the process to move the IO die to 12nm. I'd guess there's some inefficiency from being a clever hack and not exactly designed for purpose.

Additionally, the X570 chipset supports a lot of peripherals:

- 16x PCIe 4.0 lanes + 4x lanes to the CPU - 12 SATA 3 ports (some PHYs are shared with PCIe lanes so you can't have all of both) - 8 USB 3.0 10Gbps (I'm not going to google the "official" nomenclature, ugh) - 4 USB 2.0 - Other things like SuperIO and SMBus which don't use much power

Far more peripherals than M1. (Probably, it seems there's still no detailed specs about the thing anywhere).

Then there's the process advantage, 14nm GF to 5nm TSMC is a huge difference for all the logic involved. The advantage is dampened somewhat for IO because a significant portion of the power is used to drive the signals out of the chip, which is not affected by process changes. Apple's PCIe 4.0 PHYs may be more efficient considering X570 is a first generation PCIe 4.0 design.

Also, the power consumption of X570 is not that bad for what it is, 7-10W [0]. AMD must be a stickler about the 15W TDP because the fan seems unnecessary. This article is basically the worst case scenario: small heatsink on a cramped ITX motherboard in a passive case with no airflow. Maybe BCLK overclocking would run the fan? Or a dust clogged no-airflow case in a hot climate running all the peripherals at full bore?

[0]: https://hexus.net/media/uploaded/2019/7/b3affde4-8a75-4475-b...