oh well, in that case then go for it. I’d say you’ll be more than fine for 20 persons on any game. I wouldn’t be surprised to see it handle way more than that.
How many games will it be serving at once, just one? Oh yeah, and grab a copy of CentOS for your OS. Serves games (and everything else) a lot better than Windows, and there’s dedicated Linux server binaries for just about every multiplayer game in existance.