It appears that Microsoft have more plans up their sleeves as they now allow game developers the use of a seventh processing core, on the Xbox One. Formerly, both the Xbox One and the PS4 ran with six of their eight cores, with two cores allocated to the general system functionality (such as the OS and drivers). Although the new SDK and firmware (leaked by a hacking group called H4LT) unlocks more potential for game developers, they do not get to utilise the full 100% of the additional core. Instead they can utilise up to 50-80% of this core for performance in their games.
Both the Xbox One and the PS4 run with an x86 architecture and have two modules, each with four processing cores contained within. The Xbox one runs with a custom 1.75GHz AMD, whereas the PS4 runs with a custom 1.6GHz AMD CPU. This being said, both consoles are very similar and small distinct differences can be seen between both the GPU in the PS4 having a slight advantage over the Xbox One and the CPU in the Xbox One having a slight advantage over the PS4.
With the current news of the seventh core, this pushes the edge towards the Xbox One in terms of core processing power, however both consoles have a brilliant future ahead and 2014 and 2015 have been very good years for gaming.