Hi Parsad,
This makes sense, but I don't think it's the case. All other sites stay fast during the time that I'm having trouble with this site, and I'm with Teksavvy, who are pretty good about letting me know when they do maintenance. My package also gives me access to PEER1, a pretty fast internet backbone.
I'm on a Mac and don't have anti-virus software or anything else that could be slowing down this particular site, and when I get the slowdown, I get it on both my desktop and laptop.
Your theories were good, but I think it must be something else, unfortunately :-[