Some suggestions:
- remove any software surplus to requirement - if you dont need it remove it
- reset windows firewall back to basic and open only what you need
- minetest uses a udp port for connecting clients
- exclude minetest from antivirus scanning
- create a batch file to start your server example
C:\Shared\minetest\bin\minetest.exe --server --config "C:\Shared\minetest\worlds\Deasanta 2\minetest.conf" --worldname "Deasanta 2"
- you will need a minetest.conf file (copied and modified from minetest root folder) that is specific to that world.
running with --server means no gui thus pure minetest server
- when using a batch file you can use task scheduler to start it automatically when the server (pc) restarts - linux users may call this a cron job
- use taskmanager (ctrl alt del) to work out the best config. you can set the affinity of the process to run on a sinlgle cpu core while leaving the operating system and other processes to run other or the remaining cores.
- when you have figured out the best cpu / core / affinity / priority you can modify your batch file to run minetest that way using the start command line option
see
http://www.robvanderwoude.com/ntstart.phpfinetuning tcp/udp in windows is a complicated trial and error process can be done but can make run as fast as a small dedicated linux box
alternate option where lots of help would be available is to create a virtual machine in xp using virtualbox with a lean distro on it like debian
see website virtualbox.org