This site is hosted across 2 servesr (one web and one database) - each with 1GB of RAM and I think the processors are 850MHz - 1GHz.
At any one time there are at least 4-500 users online on this server...often as many as 800. vBulletin.org is not big enough to need it's own server yet, and we couldn't afford one if it did
The speed and database error issues should be fixed now, thanks to Chris Schreiber