Why is the game running slowly in multiplayer?
If it’s online play you’re having problems with, then make sure you have something faster than a 56k modem, or you will have to accept some degree of lag. If you want to avoid lag, get Broadband or Cable, and only play with players who have a ping of less than 200ms. I would certainly recommend that you have a high-performance PC for online play, and LAN gaming as well. With a 1.5Ghz or higher processor, a supported 32Mb graphics card and 512Mb of RAM, you can’t go wrong.