Microsoft limited some areas of the TCPIP stack so it doesn't work as a server past a handful of users. This can be tough to test until you get enough users.
For servers of such, why not move to Linux since it doesn't have that limit?
Another brutal cost to Server 2003 besides the OS cost is you may find the cost of firewall and antivirus to be more than you expected.
I'm a programmer - and i'm looking for some information on hosting a game i've written.
The game is quite a large project and will support about 2000+ users. I was wondering what the difference would be to hosting the game server on XP Pro on a fast connection with a fast box at my location, to hosting on Server 2003 (on the same box/connection).
If I was to install Server 2003 instead on this box, what would be the difference? Would XP Pro hold up?