Need some help

I am no expert in dedicated servers and their abilities.

I was wondering how many slots would I be able to hold in gmod with this dedicated server:

15 Mbps 80 GB 100% Xeon 2048 MB RAM

This box is owned by a family member of mine and he does not need it from now on.

The cpu ghz and how much cores?

1 Xeon Core and 2.33 GHz cpu

One core cpu :S? Vista or XP?

XP

Try 12-14 and if you don’t notice any major lag, hop to 16 as max.