WP puts my server down

Hello friends.

My wp autoblog has 100 000 posts in it and just recently it started overload my vps box with 1gb ram on it.
I wanted to hear those of you who had similar problem and what did you change in server configuration?

I did all the simple stuff like compression enable,cache,set expiration cookies on graphics.What else can be done?

Thanks

are u pinging those 100k posts ?
check apache & sql log

cheers

Not at once but they all were pinged