Core 1 has always shown more load than the other cores. I tweaked this setting for X1 and it wasn't too bad. In X2 it seemed to get worse and with X2a it's horrible. Core 1 is 50% or more all the time while some of the other cores show almost no activity.

Has anyone else experienced this? Something about those new C++ libraries has changed the way things are running here. At least that's my suspicion.

Same for me here, Core 1 runs hotter, but from X2 to X2a there has not been a change I've noticed.
What tweak did you do ?
Isn't Core 1 running higher just the Operating System, not Sonar ?

I went into the system and disabled core parking. That did something in X1 but seems to have little effect in X2.

Guys there is a ini setting dealing with core scheduling that for the life of me I can't find on the forum via search.  It is ThreadSchedulingModel. It will take 0 through 2  as data.  I believe it can help in smoothing out core usage. I have mine set to 2.

You should find it in the Preferences Audio Configuration File.   

I'm not seeing anything weird. X1->X2->X2a all showed the same, which is relatively even. 

If I run something like Omnisphere, and not much else, the first core shows a bit of spiking, but never peaks. The more tracks/plugs/synths I add, the more balanced it becomes. Overall, it's much better than 8.5.3 when it comes to balance.

On AMD here.

Just checked, and my ThreadSchedulingModel is set to 2.

I never thought about that setting John, I'll check it out. I know I had it set to 2 previously but perhaps it changed.

Page 1307 of the Sonar X2 Reference Guide ("Initialization File Format") :
 

0 = Same as previous versions of SONAR.

1 = (default) Better thread balance. Model is more

efficient and can provide cycles for other tasks.

2 = Additional worker thread is created. This may result

in improvement with Quad processor systems or higher. Not recommended for Dual processor systems."

 

I think it is better not to change any setting (like this one) if there is no REAL problem.

In my system, the 1st core works more than the others, but there is no problem with it, so i did not change anything.

Sounds like more good advice. I checked the config file and found everything set as it should be. I think my solution will be to simply turn off the performance monitoring widget in the control bar. Small things like that really bug me so perhaps it's best if I don't know.