as far as I can tell this shouldn't happen.
I tried to replicate some of it since Waves plugins are often very CPU intensive. While testing them a year ago, I could only use one or two instances of H-Reverb or a hand full of Scheps 73 before my CPUs couldn't handle them anymore.
I just put on 32 instances of Channel-E with no problems whatsoever.
Could you please do the following (I'm translating back from German to English, so things might be called slightly different):
- Click on the Apple Icon and on About my Mac and tell me what kind of Mac you have. Mine's saying Mac Pro (early 2009), 2,93 GHz Intel Quad-Core Xeon
- In Logic click on the little arrow right of the beats-display and set it to "own" (or something). Double-click on the CPU/HD part of the display. You will get a floating windows which can tell you when your systems overloads (CPU or HD usage). Let Logic run and see what it shows.
- Did you put the I/O-Buffersize back to 1024 while mixing?
- Please run the activity monitor of your Mac and see if there are programs running that use a lot of your CPU's power. It would be good to only have Logic running.
Now something different:
If I saw correctly on your images you are using the busses in parallel only, just like you would when you create a buss for parallel drum compression.
This means all your channels go directly to the output and are doubled through the busses. I don't know if that was your intention.
You also seem to create a direct feedback by feeding the output of each buss directly back to its input. I recreated that and it seems the feedback will only occur when the Send is almost pulled up all the way.