There seems to be some confusion about the difference between quad-core and octa-core processors. In the desktop and server world octa-core processors are built using the same core design replicated across the chip. However for the majority of ARM based octa-core processors there are high performance cores and core with better energy efficiency. The idea is that the more energy efficient cores are used for more menial tasks while the high performance cores are used for the heavy lifting. However it is also true that all the cores can be used simultaneously, like on a desktop processor.