drives

I have a .iso on my C drive. Does it take longer to install if it's to another drive? If so, would it take even longer if the .iso was on an external drive?

reading from one physical drive and writing to a second physical drive can be done simultaneously since they both spin independently.  the data transmission speed of moving data from one drive to another drive is negligible compared to the physical constraints of reading and writing to the same drive, where the drive actually has to wait to read the data in the first place, then wait to write it.