You know PJ, I don't have one to test anymore, but I think a lot of it is the improved IMC from the Ivy architecture. Just think of the difference from Sandy to Ivy memory clock wise.
Regardless every IC has been so easy to run in quad channel as long as you have decent kits. Still have BBSE to test but I think 2600 8-11-7-22 should be doable which should be very strong for any 3D benching.