I had one issue - while a project was running, drop a waves (latest version) reverb into the effects bin, screen went white - but sonar captured the error and asked me if I wanted to send it in.. Sure!
I just ran into a new one. Dropped in R-MIX on a mono track in the console while sonar was running. All the visual activity was drawing on the far left of the window. I dragged the selector box towards the left to drop onto the image and the screen went white and came back - the song stopped, and the track it was in kept going - but it was a recursion echo that began to run away, this time no automatic sonar error capture, had to jump quick and kill the audio engine - nasty noise.
I am running on an AMD 64 bit 6200 2 core, on windows 7 with current updates. Sonar 64 bit. No other programs loaded on my machine - its JUST for sonar.
Loving the take lanes for audio - automation lanes - and the zoom feature in the timeline - and Breverb - and the new left/right button lasso changes - and the audio engine update . Not sure about the Roland R MIX tool though, I will stay away from it for a while..
After three days - wouldn't change my decision to go to X2 AT ALL.
Best Regards,
L