$149 ARM big.Little CortexA15 + A7 octa core board.
http://www.cnx-software.com/2013/08/01/149-hardkernel-odroid-xu-octa-core-big-little-development-board/
It is 5 times faster than Pandaboard EX probably. Look at the benchmark result.
http://www.hardkernel.com/?b152