What is the power consumption per channel for a PC?

Question

Electronics

What are the main elements pulling 3.3V and 5V? And also -12V, and how much?
I know that the chipset is powered by 5V, high-end chipsets can consume up to 6A through this channel. Also, the SSD drive consumes 5V. High-speed drives can consume up to 4+A during operation. All peripherals, keyboards, mice, charging devices through the USB port of a PC, etc. use 5V. And what else? And how many.
Also, what consumes 3.3V? And with what appetite? How much can be the maximum load on these lines?
Same question for -12V.
ps are mainly interested in the maximum values ​​for "desktop" hardware. For example, I know that the video card consumes 3.3V (most likely for memory, but I'm not sure), but how much is not clear. Well, the ram still hangs at 3.3, but again, the consumption of one memory chip could not be found to calculate.

Answer 1

-12V. no longer used
+3.3 processor power
maximum values ​​- see PSU parameters

Answer 2

The correct answer is not to bother with the calculation of power along the lines, but to calculate the total. The largest consumption goes to 12V - this is a processor and a discrete video card.
For example, let's take the Seasonic Prime 1000W, it has only 125W (total) on the 3.3V and 5V lines.
And if we take a modern PSU, then it will have a conversion from measured to 12V, and already from 12V conversion to 3.3 and 5. Which gives almost 100% power at 12V.
-12V is not used at all now.

Answer 3

Here is an example of a block for powering the motherboard from one external 12V source. There, in the instructions, currents are prescribed for all outputs.
mini-box picoPSU-120 120W DC-DC ATX power supply