The minimum recommended system power for the ASUS TUF RTX 5080 GAMING OC is 850W.
Depending on the requirements of the other systems and the quality of the power supply unit, the RTX 5080 could push it to the limit.

So far completely sufficient for me.

Yes, 850 watts should be sufficient for the RTX 5080. The RTX 5080 has a TDP of 360 watts, and an 850-watt power supply provides enough power for the graphics card and other system components.