I've successfully used a RPi 3 for Octoprint (as an OctoPi) but would like to try using a RPi Zero with a Prusa MK3S. I do know that performance is severly lacking if both wifi and video feed is used during a print which I intend to do.
Now to the question, RPi Zero is supposed to be able to press to another RPi Zero for added performance. Has anyone of you tried that and if so, does it work well with Octoprint? Would the added performance be enough to run prints and video feed over wifi?
It isn't. Sure, if you have a single computer doing two unrelated tasks, you can split those two tasks up to two computers. But there is no functionality to make a raspberry pi zero perform an arbitrary task faster automatically just by adding a second one.
What you could do is only run OctoPrint on one raspberry pi, and run mjpegstreamer on the other. At least that means that if the camera stream bogs down the cpu due to wifi activity, it will not interfere with the print.
you can use a second pi zero just for the webstream
As daniel's suggested, outsourcing the mjpg_streamer for the webcam over to a dedicated webcam server is exactly what you're looking for. In fact, you can repeat this multiple times with multiple Zeroes for cameras that you can re-use for other projects.
I move mine around. I place it above the 3D printer for a downward-looking video. Or I can place it in front of the printer to see it from there. Or I can just move it somewhere else and temporarily use it for some other project.
Thanks for the answers. I've printed a new case for the RPi3 and will use the Zero for something else. 