Yup I noticed this too, but it is also slow cuz the MySQL database is getting larger and larger, which takes a little longer to load.
Of course it is a good thing to increase your site speed at your hosting, but maybe you could delete all non-active members first and see if the speed increases.
There are maybe more then 2000 members that haven't post anything from July or something. I think you could just delete them and see what effect it has.
My experience is that the board will run more smoothly and that way you don't have to buy a larger package from your hosting.
Just my two cents, hopefully you agree
