mjammer
I am suffering the same problems since upgrading to Sonar X3c, crackling and popping on the audio, also the track drops out during playback, I am using a Native Instruments Komplete Audio 6 which worked very well with Sonar X1, but has had problems with X2 and now severe problems with X3c.
I also run Ableton Live 9.1 and do not have the same problems, I am contemplating dumping Sonar because there are just too many glitches in the software that they release and I am sick and tired of being used to beta test programs.

Completely different issue here to the OP (including symptoms_ so I'm not sure why you are posting on this thread, esp when it was found to be a drivers issue.
 
I am running Sonar X3C and I'm running Komplete 9 and a Maschine. No issues whatsoever. Go figure :)
 
BTW just because something  is not working right on Sonar and is working right on Ableton does not mean to say the issue isn't your system. You may also need to configure Sonar correctly and disable intel speedstep for instance... (guess out of the blue).
 
Please start a new thread in Sonar X Forums, after updating your footer first so it shows your system specs (see mine). May I suggest you go through this thread top to bottom first and try what has been suggested because initially we are only going to rehash what has been said here so it will save us a lot of time for you to tell us what you have done to try and fix this (after looking at this thread).

> it doesn't make sense to suspect every setting throughout the system that was so happy before. It makes sense to suspect the newly added part that isn't working.
 
Ah well you didn't tell us it was working before :)

Sorry this is a common misconception. All software has dependencies, what worked together right before, may not work together right afterwards when a piece of software is upgraded or for a brand new install. This new piece of software may require a later piece of software to plug into for it to run stable. Hence we should always be running up to date software unless a rollback is required because of some bug (although we would then look to see if the firmware would need upgrading first)....
 
Often we see issues where people say X2 was working fine, then they upgraded to X3 and it wasn't working any more. They proclaim loudly therefore that X3 is at fault as they perceive logic is on their side- but actually they made an assumption, and completely the wrong assumption!!!!! 99% of the time it's their system configuration otherwise it wouldn't be working for everybody else. If you don't believe me ask Occam.
 
BTW Sonar X3 works great for me and is stable.