Not as clear as it seems - a console is dedicated to graphic power and doesn't have to run windows and all the background crap to boot ..at its release the PS4 was on a match with frame rates of a high end PC costing £1500 but 5-fold cheaper, and the power of even the most modern PC will fade at the 4k challenge.
The PC / console comparison has to be taken at face value and not and yes raw power high end PC will win but with all the extra work a pc has to do it eats away the frame rate even though it holds an independent graphic card/chip - the bottle kneck is its multi tasking and always running in the background regardless, i used to build them and squeeze every over clocking frame rate out of them but have to admit as a stand alone games console it has only had less than 30% of it true ability experienced with the release of the fast track games .... Look up the the snowdrop engine which aims to utilise about 70% of its power ... its several months away but impressive.