There was Noctua D15 numbers on a review here on Toms, though I forgot which one.
Basically, in term of cooling performance, at 100% fan speed the D15 win against the DR4P by ~10 degrees (50 vs 59.8); and at 50% fan speed ~19 degrees (53 vs 71.8).
In term of noise, the D15 registered 25.7/33.6 dbA at 50 and 100% fan speed respectively, compare to the DR4P 18.7/20.6 dbA.
The most formidable adversary for both cooler is the Scythe Mugen 5 which is cheaper than both of them, does not block any RAM slot, and maximum cooling performance is only 5 degrees less than the D15, while maximum noise is practically the same as the DR4P, 20.8 dbA. And for those of you who dislike blinking LED, it only has a single tower and one 120mm non-led fan.