It turns out that it’s Google toolbar, try uninstalling it and you will see the difference.
I tried installing the latest version of Google toolbar but it didn’t really make much difference.
It made some difference when I disabled some buttons on the toolbar though, such as bookmarks.
My buttons are now: news, pop up blocker, PageRank, spell checker and Autofill.
Probably some of these buttons try to contact some server for some reason when you open a new tab and it makes everything slow.
Hamid Alipour is a partner in Codehead, LLP with his wife, Tess. Hamid speaks 12 markup and programming languages [Yes, 12: PHP, CSS, Ajax, JavaScript, HTML/XHTML, Java, Python, C/C++, ASP, Visual Basic, Scheme and Action Script]; has a penchant for solving the unsolvable; an affinity for clean, hand-written code and is a Zend Certified 