Xenforo Server Optimization

I currently have a linode 1024 ubuntu server running nginx that has been great for my website but our forums have been slow, clunky and users have had issues posting. I am not sure if it's a server issue or xenforo issue. My site is brand new so I don't have a ton of money to throw at this but would like if someone can work with me in getting my forums nice and snappy like my website I will gladly pay your fee. Thank you