forum slow to load all pages suddenly... Hosting company says its the forum

[vwjunkie]

Hi,
My forum is suddenly very slow to load the main page, or any page you navigate to. I'm running version 4.xx. It has been running for over 3 years with no loading speed issues, but suddenly started taking a very long time to load. Upon contacting the hosting company, they are saying I should disable extra plug ins, optimize the database, etc.. I'm only running 1 plugin (miserable users) and i did optimize the database which was no help. The forum is small, low traffic (usually 8 to 10 people on at a time between registered users and guests) and all pictures/videos are hosted remotely through photobucket or youtube. They also suggested I step up to a dedicated server or another type of server they offer, both of which are 5 times or 10 times what I'm paying now. I'm kinda suspicious they are trying to sell me something and have changed some kind of setting to slow down the speed. It was literally an overnight thing, one day it was like it always had been, the next it was super slow. Nothing that I know of changed on the forum, no crazy increase in traffic, 100 new posts or something of that nature etc... I'm hosted with TMD hosting if anyone has had any experience with them. Any real way to check whether the slow loading is because of the forum or because of the server/hosting?

Thanks for any help,
Jason