Minecraft doesn't have a player limit, so it is just the max value of an int 
I wonder how that would look in practice.
Doc Freemo 
@matrix cpu and network bottlenecks. Once you reach the limit everything gets really really slow and starts skipping, if you push it far enough then you start getting timeouts and its so slow you cant even connect as everythign times out.
In theory more compute resources would delay the problem. But since compute resources are finite and hav e anon-linear relationship to compute problems, its a ceiling you would hit on any system really.
@freemo
How much? Was it due to lack of resources or just the game not being made for it?