Most modern mechanical hard drives have initial access times in or around 10 m/s. Once the data is off the platter and on the internal BUS of the computer, it shouldnt matter what the data source is. Most modern hard drives (home office) have a SATA II interface. SATA II has a 3 Gigabit per second throughput. Current USB throughput is 480 megabits i believe...in either case loads of bandwidth to deliver the goodies.....or sound bites...sorry on a post xmas diet!
cheers,