Thanks Rich,

The speed I mention was for a copper conductor at room temp..it will have different speeds in different mediums ie; in a vacuum.

My point being...if you have 2 identical circuits hooked up to a say light bulb and one is AC and the other is DC and they are turned on at the exact same time the 2 bulbs will start to light up at the exact same time. Of course the DC lamp will get to full brightness quicker..because the voltage doesn't fluctuate. But we're talkin milliseconds.