Hello Alexey
I did some tests as you requested.
For information my PC has a i7-8700K processor running at 3.7GHz and it has 32GB of RAM.
1.
Opened Cakewalk by Bandlab
Loaded the REPLAY_080322-4.spp preset
(all 24 x Track to Output Monitor set to Slow)
AZ Controller set to MIDI in and MIDI out "None"
Refresh Frequency set to 25ms
Loaded Test Project, 48kHz, 24 audio tracks and 9 buses, into Cakewalk by Bandlab.
CPU loading 12%
Fader response poor
Pressing play and moving a group of two faders makes little difference to CPU loading, saw a peak of 13.2%.
2.
Changed all Track to Output Monitors to Ultra
Project will not load.
3.
Delete all feedback events from the Track to Output Monitor controls (but did not delete the Track to Monitor controls, which are still set to Ultra)
CPU is under 1%
Fader response is very smooth
Playback is smooth
4.
My current 'live' system uses no Track to Output Monitor actions but instead uses 8 sends per track as the means to route tracks to buses. The full system uses two AZ presets with a total of 466 controls (a much higher number of controls than the test preset I sent you).
I loaded both 'live' presets and connected to my usual MIDI ports, including MIDI routing via MIDI-OX.
Set Refresh time to 25ms (which I use in my current system)
Loaded test project to Cakewalk by Bandlab, running at 48kHz sample rate.
24Tracks, each track with 9 sends, 10 buses
All 24 tracks loaded with test audio.
Project loads okay
CPU loading is under 5%
Playback is very smooth
Fader response is very smooth
Reduce number of track sends from 9 to 1, CPU loading drops to under 2%
Add 6 Track to Output Monitors, set to ultra, add one MIDI feedback action to each monitor.
Project loads very slowly.
CPU loading rises from 2% to 13%
Fader response very intermittent
Playback is very jumpy
Remove MIDI feedback action for all 6 Track to Output Monitors (but leave the Output Monitors in preset)
CPU loading drops from 13% to 2%
Playback is very smooth
Fader response is very smooth
SUMMARY
Adding even a small number of Track to Output Monitors with feedback events has a dramatic impact on CPU loading and makes the system almost unusable.
The CPU load is only impacted when each Track to Output Monitor has a feedback event
My current 'live' system has a huge number of monitor actions all with MIDI feedback outputs BUT my current 'live' system has no Track to Output monitors.
My current 'live' system uses 24 Track Input Monitors with feedback actions. These have no big impact on CPU loading
I am running Cakewalk by Bandlab. I did one test with an old version of Sonar Platinum and the results were similar.
I did one test raising the refresh frequency from 25ms to 75ms. It made no big difference to results.
So my tests suggest a problem with the Track to Output Monitor action, when it is linked to a MIDI feedback output. It makes no big difference to CPU loading if I connect AZ to MIDI ports.
I hope this helpful to your analysis of the issue.
Regards
Robert