@marcusgreen I only can give you an estimate.
130 users and about 200 activities will normally work, even though it might take quite some time before the results appear.
With more than that, it gets very buggy.
A gradebook with 150 users and 350 activities might load, but most of the time you won't get the results.
The main problem: As soon as you go to the gradebook it starts loading the data. A better workflow would be to choose your settings and then press a button to load the data.
That sounds like an excellent "rule of thumb". I didn't know if you were referring to 1,000, 10,000 or 50,00. Now I have a very good clue. I am very interested in working with #Moodle on low powered devices such as #MoodleBox, i.e. on the #RaspberryPi so that might give me a good platform to experiment.
I am not going to build that AI Visualisaion thing but I am very interesed in general performance issues.