Godaddy works for me, though it is not as fast as I would like.
My problem is any kind of web mail, especially google's gmail. Mail programs are very intensive, and it just killed my firefox; every window was agonizingly slow, or the whole screen would fade - VISTA does that, when a program is 'not responding'. It seems like VISTA has something in it that hurts Firefox.
But I found a solution that might work for you. Instead of opening up different tabs for each thing you are doing, open a 2nd browser window. Run the slow program in this new window with no other tabs open. So its isolated in its own browser. both browsers can be firefox, or whatever you want. if you isolate the slow program, then in the other browser, each tab should work fine.
Try it and let us know,
Kevin