The APW3++ is supposed to be rated for 1200w on 110v. You can't run 3 minis on 1 APW without 6 pin splitters which I believe you're not supposed to do. However I am going to try to run 5 of them on 2 of these PSUs
The mini draws like 350W overclocked. You can likely run three of them on one APW3++ (though it's rated for only 1000W @110, I've never had a problem going over with any of mine--not suggesting others do it, just saying).