...Furthermore, this is the first time I have ever heard of a HP loss using an O or X ring chain. Until isee some definitive proof of it I am going to raise the BS flag. ...
It's almost entirely a weight issue. Oring/Xring chains are heavier than standard chains, so it takes more energy to change their momentum. In cruise, they won't use significantly more HP while they are moving at a constant speed (If the Orings are tight it will use more energy to overcome that friction resistance to bending and unbending around the sprockets, though.) On acceleration, the extra weight will consume energy that would otherwise be coupled to the rear wheel, not only to move the chain, but also the added weight gained by the bike overall.
Oversize tires have a similar effect, by the way, as do 20-200 cheeseburgers. 
Cheers,
Not sold.
If that were the case why does every sportbike racer use an o/x-ring chain? Those people excel at getting every bit of HP they can out of their machines. While I see the merits of your argument I can honestly only see a fraction of an HP being lost. Racers don't care about wear on their chains and sprockets because they are changed virtually every race and numerous times during practice.
And, I'm not selling. I just explained the rudimentary physics of it, which you can feel free to verify, refute, or quantify scientifically. If you have a "belief" that you are loathe to change, then I'll not convince you otherwise.
The weight issue got me thinking so I checked out DID's site. According to their documentation their standard non o-ring chain weighs in at 3.71 lbs where as their 520ERV3 x-ring chain comes in at 3.30 lbs...lighter.
What exactly are you comparing? 530 to 520 oring/xring? I couldn't find any on that chart with a 3.71 lb weight.
I will add that they also list a number of 520 and 525 chains that are heavier than the non o/x-ring chain so it could depend on which one you get.
Welcome to the world of specsmanship.
There's a danger to applying parts for racers onto street vehicles. Note the plate thickness differences. One could argue that plate wear during a race is less than pin wear, requiring a different need for street bikes that use a chain in conditions where plate wear may be more significant, or where inspection intervals are farther apart.
Also, the DID chart contained no pricing info. Could be that the plates can be smaller if more expensive or exotic metals/materials are used. I didn't follow the money, just the physics.