Pau08. Your MacBook Pro, if recent, will be usb3 and NavV does not specify its USB and may not even be usb2. Undoubtedly transfer to the USB card will be much quicker if the card is in the computer and for that reason IF you choose to upload new maps to SD card then do it to the slot in your computer.
Now a big negative comment re NaV V : why hide the SD card in such a ridiculously inaccessible location which requires a screwdriver for access? My Zumo had a fabulous flip cover for easy access.
Now a big negative comment re NaV V : why hide the SD card in such a ridiculously inaccessible location which requires a screwdriver for access? My Zumo had a fabulous flip cover for easy access.