Electrons in the conductor are actually kinda slow, it's on the order of millimeters or centimeters per second. It's the electromagnetic field propagation that is fast. That is, if you have a conductor cable, and apply voltage to it, the individual electrons inside it will proceed very slowly, but they all will start moving almost at the same time along the length of the wire.
PCIe uses differential signaling which should approximate AC so the electrons do not have a net movement down the wire at all, they more or less just wiggle back and forth. In reality there is likely some DC bias resulting net migration but a signal trace should be very low current; you're probably looking at electron drift velocities in the range of a 1-2 millimeters per hour if were to hand-wave a guess.
The way I like to visualize it is a line of billiard balls. You smack one end and all balls move a bit maybe one place over but the force (charge) moves through them moving the last ball. (Yes charge isn't force but can be made into a electromotive force EMF via inductors, coils etc.).
This is also a flawed analogy as the whole line of balls will still move slow. It's more like tiny balls on a loudspeaker. When you apply energy to the loudspeaker a pattern depending on energy on frequency will develop. It's more the speed at which this pattern can change rather the speed of movement of the individual balls
I'm thinking more along the lines of the spot where the balls were is a hole which the balls now occupy. The balls moving isn't the point I was trying to make it was the force from one end to the other. Not the greatest analogy I'll admit.
I'm not sure I understand what you're saying it almost sounds like you're referring to impedance.
Electrons move fast, though not nearly as fast of the speed of light. However, they don't go in a straight line. So if you mark a single electron and look at it from afar, you will see it move very slowly. But if you look closer, you will see it jiggling around with a slight bias toward a direction.
What goes at nearly the speed of light is the "message" that electrons should move a certain way. If you want an analogy, if you blow into a flute, even though the air is moving slowly, the sound travels fast.
You're both right. Individual electrons can move at high speeds (not c), but the overall flow of electrons in a wire is very slow. This happens because individuals move in random directions but the group has a slow push with the current.
Imagine people going to the shopping mall. Once in a while someone goes in and an hour or two later they come out the other door 10m away. But they travelled a lot more than 10m. You just didn't notice from outside.
> Individual electrons can move at high speeds (not c)
My memory may be off but as I recall the fermi speed in copper is only around 0.5% of c, rather far off. What does propagate at speeds on the order of c is the EM field, which is what most people are actually talking about when they think of electricity moving down a wire. But, it's still something around ~60% of c in a copper transmission line.
