I have terrible latency with my midi keyboard now. I'm using Ez drummer to add a ride, but it's about a half second off. I'm also getting weirdness with track alignment when making changes in the pro channel. 128 samples, 7.3 roundtrip latency. I haven't made any changes to anything...I'm kind of stumped.

I have had trouble with latency with X2a also on older projects. I find that when I turn off "FX" the latency goes away.  So something is up with audio plugins.  So I turn off fx, record the new midi, then turn the FX back on.

I have deleted and reloaded audio plugins on one project and that seemed to solve it there.  But that can be tedious on big projects.

I took your advice and went through the plugins one by one. This song has 5 tracks (yes 5). The pro-channel is on in all 5. I was trying to add a ride with ez drummer to track 6. I had one instance of R-mix running in track 3 to eliminate a noise on the bass. Deleting R-mix solved my midi latency on track 6.

Plugins like R Mix add a lot of latency.
 
Other culprits are convolution reverbs like Perfect Space, or look ahead efx like the concrete limiter, LP64 EQ and multiband compressor. etc.
 
These should be turned of whilst tracking.  This should not have changed since X2a, but would be happening with any version of Sonar.
 
 
edited for typo

+1 good call jb101

Bob Bone

I was getting the same in some, not all of my current projects. Some projects would be fine and others would exhibit this half second delay when playing with my MIDI keyboard, and only after upgrading to X2a.

Fixed it, but I cannot say how. I was changing all sorts of buffer settings and stuff. Might have been because I had turned off, then on, an effect or two, but the delay appears to have gone, in all projects.

Very weird...

I'm still getting strange little things when turning on or off pro channel modules. I'm pretty much trying to get in the habit of hitting the stop button before doing anything. Not so Gap-less in my opinion.