Are you saying that you want your domain on another server?
It might help to find out why your site is slow. It could be a few things:
1) Your connection to the site is slow.
What's the URL so we can take a look?
2) The server is under a heavy load.
If you have shell access (SSH or Telnet), log in and type 'w' without the quotes, and see what the Load Average is.
If you think there's a problem on the server, contact support by submitting a request in the control panel.