Quote:
Originally Posted by kennyc
The SD card is a serial interface
SD cards typically have transfer rates in the range of 10-20 MB/s,
USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0 was intended to go only as fast as 240Mbps, but in October 1999, USB 2.0 Promoter Group pumped up the speed to 480Mbps.
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Actually SD cards have 4 bit wide parallel interface, not serial although there is a slower serial pin for legacy devices.
USB 2.0 sounds like a lot at 480 but this is bits, not bytes so the theoretical maximum is 60 and that is hard to sustain. It is unlikely the eReader can sustain anything close to that speed. It practice both SD transfer and USB transfer is likely to not take very long anyway so it is a matter of convenience. If you have an SD card reader in your device it is probably quicker than finding the USB cable around here somewhere.
Dale