I just learned something replying to a feature request by accident that is slick enough to warrant sharing -
 
Situation - Working a project with high CPU usage, but you want to step away for a bit. Easiest method is to save manually and manually disable the audio engine. This drops CPU performance to zero while you are off doing your thing.
 
Unexpected surprise - If you have manually disabled (i.e., it didn't dropout) the audio engine, and then hit spacebar; SONAR brings the audio engine back online and begins playing!
 
Never realized this neat trick, but worth noting to folks interested, especially if you "walk off" while working on projects regularly.

You can also bind 'Run/stop the audio engine' function to a hotkey; it's been the accent character on my keyboard for years.

Hi. I use this as well. I have had "Y" as my hotkey for years. Good tip, Michael.
All the best.

Brilliant tips, thanks guys.