Optimizing vB database

[Whatah]

our site www.yugiohforums.com
currently running vB 3.8.4 patch level 2
Treads: 37,922, Posts: 562,787, Members: 15,793

According to our host, with our activity (100 online members + 300 guests) and our database size (2,000,000 lines) we are hitting the limit of shared box hosting.

We are starting to get "500 Server Error" from time to time, according to our error logs it is because we are exceeding max_user_connections (50) caused (according to our host) by the size of our database.

I figure that part of the issue is database size, and other part is number of queries.

We have a few major modifications like CybChatbox, v3 Arcade, vBExperience, and vB Optimize.

We also get some active "+++++ game" threads that hit 1k or 2k posts before the game ends. Would it be possible to improve the database performance by moving some of the very large threads to an non-active subforum where posting is not allowed?

Or should i focus on removing some forum modifications that are adding queries? My host is pointing primarily to the size of the database rather then number of queries so I would love a second opinion before i commit to removing the vBExperience or Chatbox mods.



Thanks for any insight.