I too am curious about the requirements. I am looking to set up a server that can handle 30 kids hammering away at a quiz that is serving up questions, many with images. Although 30 simultaneous users is quite a small number, I think the quiz function, especially with images, really puts a load on the server.
I actually have two servers I am testing.
Server 1 - InMotion Hosting VPS-1000
Server 2 - Cloudways
Varnish turned off (Varnish results in repeated log outs...)
The second server at Cloudways seems to run a bit faster. This seems counterintuitive, as RAM is supposed to be about the most important thing for getting a server to run fast.
Does anyone know if my Hardware on server 2 should be getting the job done. It can passably serve up the quiz, but the load times for pages are often between 10 and 20 seconds. I really need it to run faster. I do know if I move up to the 2GB server level, I get 2 cores instead of 1, but I have absolutely no idea if that makes any difference.
Finally, I have noticed that I could be running Memcache instead of or along with APC, I really don't know much about that.
Any suggestions would be much appreciated.