I am not talking about LOADING the page. The problem can be mainly experienced when you scroll up and down a page with your mouse. It doesn't scroll smoothly and it lags. AGAIN, I am not talking about page loading.
[edit] I disabled NBS and the pages still seem heavy.
While you won't be able to effectively "play" Bushtarion - try disabling javascript in your browser temporarily, and loading a few pages (ignore the error message at the top of each page telling you to enable javascript) - how does it run now?
If that smooths things out, re-enable javascript, and go to ID Settings and try disabling these things in order (you can do them all at once, or try them 1 at a time checking pages in-between each being disabled), to see if anything makes a difference (both options are at the botom of the page)
"Disable Advanced Tooltips"
"Disable Live Javascript Time".
Did the problem only start recently? Can you remember when it started? It's possible you have other add-ons/extensions/programs running that are slowing heavy web pages down. If you're using Firefox, temporarily try pages in Internet Explorer and see if you get the same effect. If you have Firefox addons such as "Firebug" running, disable Firebug altogether and see if that improves it, likewise any other addons that might be "doing things" to pages.
Slow-downs while "scrolling" up and down a page will be related to processing power, and this is why I think the problem will be lying within the Javascript engine, or with other things running on the computer. Once your PC receives the page from the server, all of the scrolling up & down is done purely client-side - no more data is sent back & forth from Bushtarion.
