To truly get the benefit of a dedicated game server, it shouldn't all be done on one computer. You can, but you'll lose more than you'll gain. Now before you start thinking something like...
Oh, I only have one gaming rig or hell, I've only got 1 computer!
Before you get to worrying about all that, don't because that's the beauty of server versions of a given game. They don't need or even benefit from...
1) A video card!
2) A sound card or even onboard sound. Yes, you'll be disabling that in the bios to free up some CPU cycles and RAM.
3) A big and or fancy monitor. Any 14 incher will do because you'll just be looking mostly at text on that PC and then shutting the monitor off after setup!
It will benenfit from the following...
1) a good CPU. In most cases, a fast, 478 pin Northwood chip which is cheap as all get out now or the AMD same/same will do nicely. Stay away from Celeryon chips and the AMD same/Same of that!
2) Lotsa RAM all on two sticks. A safe bet is two, 1 MB sticks for a total of 2 MB's of system RAM. Many games can get by or even don't benefit at all from that much while running, but it makes load times faster either way.
3) Two 36 GB 10,000 rpm Western Digital Raptors in a 0 RAID array chunked to 4 or even more depending, and chunking it at 8 might be adviseable because for the little space you'll give up, you'll be assured that all files can fit in one place. You'll need programming like Acronis to do this because Cousin Billy doesn't allow chunking beyong the default 2. Acronis also has a feature which allows you to whipe the drive completey while formatting by overwriting 0's, then 1's and back and forth a few times like some security programs can do for your recycle bin.
Then you will also want Diskeeper 9.0 Pro and no, the pirated version is porked and you just let in run in the mode where it watches everything for the first 24 hours of heavy use. Turn that mode off and it still remembers everything and from there, it degrags in like 5-10 seconds, defrags things Cousin Billy misses completely or makes it uneasy to defrag.
Remember, this 0 RAID array on the drives I mentioned will give you like, 70 gigs of space on the C: drive in a O RAID array.
You'll want a excellent and obstinant security program like Norton Internet Security 2006 because I'm sure you'll take this thing online.
The server runs as host and manages all that part freeing up your CPU cycles to just run as a client. It's a nice deal. any questions?