A 860W PSU will handle those 2 GPU's even if it's just a dissent PSU. Now the AX is not just a dissent PSU. It screams quality.
You don't even need anything near 1000W. look at my system under my post. When i am gaming i use less then 400W.
and that's with a monitor and speakers. (my watt calculator is connected to everything at my desk.)
You are concerned about noise. The AX 760 (the one i have) fan first kicks in at 70% load. that's 532W.
now the 860 version is a little different. it's fan kicks in at 50%. But that's still 430W. then it starts at 20% max fan speed.
So the AX 860 is indeed a quiet PSU.
according to corsair's site the RM1000's fan kicks in at 40% load. which is 400W
Yet again according to corsair's site the the HX 1050 has a fan that starts at 20%. so that's 210W.
Here are the links.
Look at 60% load. The RM is 10db loud and the HX is 30db loud. Now look at the 860, it has ZERO db.