Chris King hubs are infamous for their noise. But noisier hubs generally have more points of engagemet...more pawls, more ratchet points.. than do quiet Shimano hubs.Shimano, in making its hubs quiet...and dont get me wrong, they are excellent hubs, are choosing slightly lesss drag and silent coasting over more points of engagement and increased efficiency while pedaling. Chirs King, White Industries and other makers of noisier hubs are making the opposite decision, maximizing power transfer while pedaling while sacrificing a bit of noises and drag while coasting.
Who does more engagement points increase "efficiency" while pedaling? But first you'd need to define what is efficiency you're referring to.
How does more engagement points maximize power transfer (compared to a hub with less engagement points)?
And I've done some simple rolling test of my Dura Ace wheels vs DT 240 vs CK R45.
The DT and DA always come out neck-to-neck and both are better than the CK R45 by a good margin. CK hubs tend to be draggy due to their robust seals. I'd take DA hubs over CK anyday if my goal is to roll with least resistance.