need some inputs to select a dedicated server

Hello,

I have a forum website(invision board) and need some inputs to select a dedicated server.
My forum has 8 million posts (Including posts and topics) in total.
Right now i am using Xeon 5260 2 bay chaisis
32 gb ram
400 gb SD
I just want to know how can we determine the server configuration ..based on what factors?
Current issues i am facing is database table crashes....
Any info on hostingsource.com , arvixe.com , kvchosting.net server hosting?
Alteatives ? Reviews ?

Thanks WordPress ...