SRAM xx1 1 x 11 drive train very noisy I have a 1 x 11 drivetrain setup on my mountain bike.  This is stock from the factory, it wasn't a conversion.  When I'm in the low gear climbing, there is a lot of chain/derailleur noise. It gets more noticeable when the drive is under more tension. Being in the low gear, the chain angle is fairly minimal, so I am really perplexed. The sound almost mimics when the chain rubs against a front derailleur when the chain is at a drastic angle rubbing against the side.

I'm afraid I am wearing out my drive train too quickly because something is not adjusted correctly.  My old 2 x 10 was virtually silent.

Addition, when going downhill and pedaling, the chain was slipping teeth quite often.

Does anyone have any ideas?

UPDATE:

After replacing the bottom bracket and spending the rest of the season fighting the noise, I have decided it's coming from the SRAM X style teeth on the front chain ring.  When the drive train is squeaky clean the noise is minimal. However after a ride or two the noise starts to come back.  It's only there when the drive train is under heavy load.  It sounds awful, like my chain and teeth are grinding together.  I can only assume it's the X teeth, anyone else confirm this on their 1 X 11?
Even though you mentioned in a comment that the high and low seemed to be adjusted properly, it still sounds to me like the 'L' limit of the rear derailleur is improperly set and does not allow the upper guide pulley to fully move the chain onto your largest cog. 

If this is indeed the case, shift into the largest cog and  adjust the 'L' limit screw (the outermost 3mm adjusting screw) until the center of the upper guide pulley is aligned with the center of the largest cog.

Another possibility is the chain gap is not properly set. The chain gap for the XX1 groupset should be between 12 and 16mm and should be set while the chain is shifted onto the largest cog. You adjust this with the single 3mm adjusting screw located by the derailleur mounting point. Make sure the limit screws are properly adjusted before checking or changing this setting.

The chain gap is the distance between the top of the teeth on the upper guide pulley and the top of the teeth of the largest cog as shown in the following illustration from the User Manual for SRAM 1x11 rear derailleurs:



In the picture above 15 is High set screw and 14 is Low set screw 

If these adjustments do not resolve the issue, bring the bike to the bike shop you purchased it from and have them check it out. My LBS has had several customers (including me) experience issues with the 1x11 cassettes for which the ultimate solution was SRAM sending out replacement cassettes and chains. (Although I think in all of these cases the issue was the chain unexpectedly derailing onto smaller cogs while back pedaling on the largest couple of cogs.)