That feature will not, or I should say, cannot be implemented. Doing so would mean that it would be impossible to unmute a track during playback without dropouts or synchronization problems. Most users would find that unacceptable, since muting and un-muting tracks during playback is a very common practice.
 
That is the main difference between an archived track versus a muted track, and why both are offered. Archiving a track takes it out of the process completely, whereas muting just disables the track's output. In this way it is analogous to a physical mixer: pushing the mute button on a mixer channel does nothing other than ground that channels' output. The digital equivalent is, after processing the signal normally, ultimately setting the channel's output to zero.

Some sort of option would be nice to have...  maybe to bulk disabling all VSTs on muted tracks in one click? That's of course if someone needs it. Maybe script of some kind...
Still a feature request :)
 
57Gregy, not sure if VST effects will act as VSTi but it is still an extra step for each track. But thank you for info, actually for now, if it works for VST effects same way as VSTi it is probably the best option!
 
I was just naive thinking muting will idle VST from eating CPU. 

Bitflipper thanks.
I understand what you are saying... 
Still it would be nice to have an option of bulk disabling/enabling VST items from mute/unmute states. 

Archiving is one way of bypassing FX and synths.
 
Effects may also be bypassed by

• Individually by Host bypass - The VST3 spec provides for a host bypass. Most VST3 plug-ins implement it and there is a button on the left side of the VST standard header to toggle host bypass. Host bypass is often available for automation. Region FX have a bypass options on the Region FX menu. Some VST2 provide a way to turn of the plug-in but there is no standard for what the plug-in does while turned off.
• Per-track by bypass FX Rack/Turn off PC Rack - these will bypass all plug-ins in the FX Rack or ProChannel. This is what archive and freeze do. FX Racks have bypass options in their context menu. The PC on/off button is the Prochannel bypass.
• Entire project by global FX Bypass - this is the FX button in the Mix Module, keyboard shortcut E. This bypasses all FX Racks and ProChannels.

Synths are bypassed by disconnecting them in the synth rack. This is the process used by archive and freeze.
 
 
 

Scook, thank you for detailed explanation!
 
This: "Entire project by global FX Bypass - this is the FX button in the Mix Module, keyboard shortcut E. This bypasses all FX Racks and ProChannels."
 
It would be nice to have this global bypass for muted tracks specifically :)

bitflipper
That feature will not, or I should say, cannot be implemented. Doing so would mean that it would be impossible to unmute a track during playback without dropouts or synchronization problems. Most users would find that unacceptable, since muting and un-muting tracks during playback is a very common practice.

Well, in Sonar/CbB that is not possible. But I do not exclude it will be implemented, if CbB will ever get any engine development (Sonar had no such development like 10 yeas long...). And such feature will take an hour to implement. Way simpler than implementing anticipative engine and can somehow compensate the age of current one.
 
There are 3 different plug-in states:
1. not loaded (no resource consumed)
2. loaded but not working (RAM is used, CPU is not used)
3. loaded and working (RAM is used, CPU is used).
 
With archiving you can get (1). With audio engine stopped you can achieve (2). Sonar keep everything in (3) otherwise. But what prevents switching to (2) when the result is muted? Nothing. Just current implementation in Sonar.
 
Note that:
* "switching" between (2) and (3) takes no extra CPU nor time, you just call "process" method on every buffer when required and no longer call it when that is useless.
* Sonar already distinguish between "automated mute" and "mute". Sure, for automated mute that is a bad idea.
* related to the previous point and "leaking" at other places when implemented, that feature introduce some plug-in specific trouble. Unexpected tails. Many plug-ins "remember" a part of previously processed sound and when asked to start again (un-mute), they will use wrong information. Not a big deal during normal audition. But not acceptable for automations and rendering.
 
You can guess at least one DAW which can save CPU on muted tracks, as default setting

Good read.
Thank you!

Excellent read.  I learned a lot.  Thanks for all the informative answers!

Right-click in th FX-bin and disable vsts's on that track only.
I'm allways using this approach when there is (too) high CPU load.