My question is if so many student (imagine more than 500) take same quiz simultaneously make the server down or not?
It depends on how powerful your servers are, but you should be very worried at that sort of level.
You reall need to use a load-testing tool to simulate that load and see what happens before you actually run a quiz with that many simultaneous users.
Thank u for reply. Actually im quiet new in moodle & still in a research part to find out how can i improve the processing part in quiz modlue to reduce RAM usage as it quiet expensive.
we have about 10 000 users , so it a bit confusing to find out a solution.