Sonar continually freezing

Since it continues to play I would conclude something else but audio and soundcard. I may not be the best brand and drivers since you have a pretty strong machine and cannot go below 256 but that's another story.

I would have a closer look at latest drivers for graphics card.

Is your computer built by a professional daw builder?
More expensive, but someone to turn to when it fails.

Just buying a stock computer is not all it takes.

Updating bios and chipset firmware on motherboard is quite harmless nowadays. I wouldn't hesitate doing it.

Just don't turn off main power until finished.

Are the plugins x64 versions as well?
Otherwise they will use a bridge like Bitbridge to run as 32-bit and that could very well be a lot of issues with these.

I had some issues with GUI visible on plugins.
Make a try closing GUI for plugins during playback to narrow problem area down.

If running bitbridge I would try jbridge which cost a few dollars. Easy to use in Sonar and just put a check in PluginManager in Sonar. Some plugins run better with jbridge.