Soldato
I would suspect that they are being overly cautious in their spec. My 700W semi-fanless PSU is happily powering my Skylake 6700K at 4.4GHz (with too much power), a GTX 9800Ti, two pumps, Aquaero, Farbwerk and lighting and it's not breaking enough of a sweat to even need to spin up its fan - despite the intake being pointed at the carpet. 1200W Should be more than enough...but as long as it doesn't cost you in inefficiency for the load you're running, who cares?! The headroom is always good for the future or just for knowing that it's not a problem.