If an ITX board requires a 19V power supply, how can it deliver 250W for the 12900K?

[cap__]

The small ITX motherboards require a laptop power supply with 19V, which usually only has 90W. They also offer the socket 1700 for the i9 CPU. Besides the wattage that is otherwise needed, an i9 can sometimes require 250 watts. How is such a power supply supposed to manage that?

[stj]

because it converts that 19v down to about 0.8v so the current multiplies by over 20x