The 500 messages is per room, and isn't a cap as such, it's a recommendation for performance reasons. Also, your calculation for 50 players sending messages at 10 per second is a little off. each client would be sending 10 messages per second to every other client. So unless I'm mistaken the message per second count would be in the order of 25,000 for 50 players in the same room each sending 10 messages a second to everyone else. For an FPS game, I believe the recommendation is max 4-8 players per room for PUN. But for other game types the player count for each room could be much higher, with a bit of interest management and optimization. For example my multiplayer RPG game will support up to 50 players per room and stay within the 500 msg recommendation.