I just installed the X3d Producer trial today, and the first thing I notice is that during playback, the time displayed in the transport module is actually lagging behind the audio, by maybe 150-200ms, at a guess? I wouldn't have been too surprised (though mildly disappointed) if the time was ahead of the audio, because of the usual latency stuff. But in this case, I am hearing the audio for beat 1 before the time displays beat 1. I think it wasn't the case in 8.5, or at least it was less obvious there.
 
Is this a known issue? The only explanation I can think of is that perhaps something is misreporting latency, so the audio engine thinks it is further behind than it really is?

Two things come to mind: possibly the Pause key was pressed, which puts Sonar into a display update 'conservation mode', and possibly the picture cache may need to be emptied.  If it gets a bunch of stuff in it the display can get laggy.  Sonar will recreate the picture cache for you, so emptying it is not risky.
 
Here is a link discussing some of the above:
 
http://forum.cakewalk.com/SONAR-X1-Display-Lag-on-the-Timeline-m2542926.aspx
 
Bob Bone
 

Just tried the Pause key - it definitely wasn't that. In fact, what I think I'm seeing is that at least one plugin (Superior Drummer 2) is playing back early. I took a screenshot and it's clear that the timeline and the time display are in perfect sync. Yet, with MIDI events right on the grid, I am hearing them before the start of each beat. Odd.

The first I'd do it apply the X3e patch. There were issues with the now time marker that have been fixed (as far as I know) in the latest patch.

I presume this is with x64 Superior so it's not the Bitbridge bug...?
 
If you disable Stop At Project End in the track view options, and just play a new blank project with the playback metronome enabled, do you see/hear a discrepancy between the Now time and the clicks? And if you then add a Superior Drummer track, which two of the three remain in sync? Or does the problem not manifest in a new project?

This can be an issue with your sound card, your sound card drivers, your sound card driver settings, video card and your PC. So info on all these will benefit you dramatically. It seems that one, two, three or 2 of 3 or 3 of 4 or all the above may be your problem
 
CJ