I did an experiment, to find out between 3.3V and 5V which motherboard power supply turns on first. However, the switching speed is so first that it's hard to see which led turns on first with the naked eye. The white LED indicates 3.3V and the green represents 5V. Can sport which one turns first?
When you are diagnosing and fixing Laptop motherboards, it's easier to focus on the fault section if you understand which section turns on first and then which turns next.
