Hi,
it is nice to see, that people are trying to get some sounds out of sunvox..Thanks for sharing your music :-)
I am also trying some sounds and will later share them :-)

a.

i dont have this problem, even when i play the demo song"city dreams" with more than 17 synth modules.
Maybe some apps are running in the background?
I allways close all open apps before i start sunvox.Maybe some other task is having a high cpu load?

If you are unsure you can see the cpu use of the sunvox plugins by clicking on "cpu usage" in the sound network menu

b.
If you want more Channels, you can make a new pattern.You can play multiple patterns at the same time.
Go into the timeline window (in the synth network click on the arrow symbol near the wretch)
When you are in the timeline windows just click on the wretch to open the menu.Then click on new pattern. Now you have another up to 8 channels.
You can repeat this step if you need more.
You also can use the timeline window for you arrangment.
You can determine, which pattern is played at a given time.