X1C now you've gone and done it...

Hi, just thought I'd add my details to the list of folks having X1C issues.

X1 Producer x64. (no mods)

Following issues I'd experienced since 8.5 with projects locking up (in not responding cycles) due to wave rendering issues associated with detailed tempo maps in projects with larger than minimal track counts (an acknowledged flaw) I'd been assured that X1C was going to be a further step in a positive direction. I'd actually found X1B to be relatively stable. An occasional issue but nothing too intrusive.

Since X1C I have encountered a significant increase in instability. Particularly unrecoverable not-responding crashes when saving a project (over a third of the time in the last 24 hours). I'm also suffering with issues from my UAD-2 card reporting it's dsp is overloaded in projects that were previously running smoothly. I must also note longer than previous project load times, graphic freezes while audio continues playback with random channels soloed/muted, midi dropouts from step sequencer patterns and other general not-responding lock ups.

There are many things I like about Sonar that have seen me overlook experiences like this but it continues to be an unfortunate occurence when updates promising improvements decrease reliability in some way. Hopefully we'll see some fixes shortly.

TaureanBlacquedetailed tempo maps

How detailed? I've noticed some folks create tempo maps (presumably by drawing them) that have many tempo changes between note events. There's no point in having more than one tempo event per duration interval. I little thinning could get you the same performance without rendering issues.

audio continues playback with random channels soloed/muted, midi dropouts from step sequencer patterns

This sounds like MIDI Prepare Using buffer being too small. Start at 500 if it's lower than that, and try increasing in increments of 100 up to maybe 1000 if the problem persists.