The motherboard takes a full-size 24-pin ATX power link from the power supply, which handles most functions on the PC. Still, there's also a dedicated central processing unit (CPU) connection, usually ...

The keying is slightly different, but the PCIe power plug fits easily into the ATX 12v socket; the difference in the keying is only one pin (pin 5 from the diagram in your link), which is D-shaped ...

There’s a hot new power connector in the desktop PC world… and by hot, we mean “literally melting.” Issues with the new 12VHPWR power connector design for the latest PCIe 5.0-compliant graphics cards ...