[SMHarman]

The PC performance specs are not likely to be the limiting factor. The network configuration will potentially slow things down more.

If you are connecting them through a router, then the routers routing speed needs to be considered. If you are connecting all of them through a hub then packet collision needs to be considered.

Others have more advanced networking knowledge than me, but if you have 15 users on a 10mb network wire then you are sharing that bandwidth evenly.

This all said. You work with a 256k upstream on a cable modem and that means a game should operate fine, if you put all the players on one machine via hubs the bandwidth allocation will be 333k each and the pings are likely to be near 0 so that should work.

I would imagine a 4 port router with each of the routers connections being put split 4 ways via a hub would be the best way of configuring this, that would give 16 connection points, one for each PC plus the game server. Make sure you remove other traffic from the network, removing services and the internet connection etc.