DUE spi DUE spi/dmaSPI clock write write1MHz 0.82 1.00 mbs (million bits/second)2MHz 1.45 2.004MHz 2.35 3.997MHz 3.26 6.9914MHz 4.25 13.9421MHz 4.73 20.8942MHz 5.33 41.45 maple spi maple spi/dmaSPI clock read/write read/write1.125MHz .85mbs 1.125mbs2.25MHz 1.35mbs 2.25mbs4.5MHz 1.8mbs 4.5mbs9MHz 2.2mbs 8.9mbs18MHz 2.2mbs 17.8mbs arduino avr328p/16MHz SPI clock read/write 2MHz 1.57mbs 4MHz 2.6 mbs 8MHz 3.8mbs
fat16lib reported SD data rates of 33mbs (million bits per second) running at 42 MHz.
I added performance results for the DUE's "extended" SPI mode. For the unconnected tests, the extended mode is faster than the older SPI API. See SPIperf.txt on the git site below https://github.com/manitou48/DUEZoo