again³
the scirra multiplayer object has nothing to do with connection speed or capacity; it uses a peer to peer connection which means that the first player to connect is the host, then the host connection dictate the number of players/performance.
now then... if you want to make a online multiplayer game using construct, the best option is the multiplayer object since is good and ready to go; but if you want to build a game with a "server", you will need to setup one outside the C2 and program a way so the server is always the "first player" to connect, meaning the server will be the host
my best advice is to make a small game using the multiplayer example inside C2 and see how far you can go with connection P/P to see if is doable, like a proof of concept so you dont spend months and discover that no one can play it because of lag