Jonathan Blow, in an interview with Edge, spoke some on the speed of the PS4 or, that is to say, the 8GB of GDDR5 RAM on the PS4.
He commented how his latest project, The Witness, ran considerably faster on the PS4 compared to its performance on the PC. "Rendering stuff through Windows has an impact on performance", said Jonathan Blow, "Since a console is just about games, that doesn't happen, and the equivalent game will run faster."
PC Gamer offered its own explanation as well stating that the Windows operating system often diverts memory throughout the PC. This can cause performance issues even if your focus is playing a game.
With this report from developer Jonathan Blow, it adds considerably to the weight and believability of Sony's claim that the PS4 is more friendly for developers.
Source: PC Gamer