[holo]

it has nothing to do with the bitrate, number of files really won't matter that much (although maybe a little).... the phone transfers very slowly, try using an actual card reader and plugging into usb, or getting a mass storage program which makes your phone act like a microsd card reader instead of going through activesync (the cause of the slowdown)....

also, different cards have different speeds, some microsd cards are faster than others....