Power draw of AMD's RDNA2-based GPUs drops significantly. ComputerBase compared each Radeon RX 6000 series model's power consumption with the launch driver of the respective card and the Adrenalin 21.8.1 driver. The RX 6700 XT for example sees a drop from 30W to 18W, while the RX 6800 XT drops from 40W to 32W.
Unfortunately, this is not the case for HDR video clips. When playing HDR YouTube clips, power consumption is still the same as before.