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Nope, it's 1/2 - 2/3 the speed of light depending on the metals used.

The velocity factor is usually 0.6-0.7, never seen it as low as 0.5.

And it's set by the dielectric, not the conducting material.

You're both wrong. It's true that the first whisper of movement travels at the speed of light, but the time until the flow stabilizes (which you WILL need to wait for in electrical chips) is actually slower than the "speed of electricity".

Oh and also: currently the idea behind on-chip lasers is interconnects that don't have this limitation. For example, PCIE is looking to build optical interconnects, which will do the equivalent of bringing every GPU 10x closer to the memory.

Optical computation would require that light switches light transistors on and off, which doesn't seem to be possible with this technology. This is optical computation in the sense of allowing light beams to be produced according to formulas.

Why do you need to wait for it to stabilize? You can keep changing the voltage at one end of the connection even if you have megabits of data currently in transit, without waiting for it to stabilize. Yes, you'll need to do impedance matching. Yes, that's a solved problem. Transmission lines.

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