Nexus 6P and Nexus 5X software encryption faster than hardware-powered encryption methods
This year’s devices run on Snapdragon 808 and 810 which are 64-bit SoCs with an ARMv8 instruction set. There are cryptography extensions provided by ARMv8 that will offer devices better performance than the usual AES hardware encryption on Qualcomm hardware.
Official response from Google officials regarding nexus software encryption:
If this news is indeed correct, you will not have to flash modified boot images in order to disable encryption on your new Nexus device. The boot images run on the eMMC 5.0 and not on the faster storage from Samsung, so they wouldn’t make your device that much faster when it comes to storage anyway.