Tweak Internet Explorer 8 Performance Using Microsoft IE8 Performance Whitepaper
Microsoft has released a document on how to enhance the performance of Internet Explorer 8. This white paper will help you learn how to fix some common settings of Internet Explorer 8 that slow down your web browsing. In this document, Microsoft explains how third-party add-on’s that are not developed by Microsoft affects performance of browser.

This is a step from Microsoft to explain the reason why IE8 may slow down on performance and speed.

In the document Microsoft quotes…
Although browser add-ons can add great new features to your browser, they can also introduce performance issues if written poorly. Add-ons cause most browser crashes, accounting for over 70% of Internet Explorer 8’s crashes. Slowdowns in Internet Explorer 8 are very often caused by add-ons – especially when you open a new browser window or tab.
In the document, you can see step-by-step guide on how to manage these add-ons and make IE8 a better browser for your needs. Apart from these, Microsoft explains some more tip and tricks on security of browser. A 14 page word document, a must read for Internet Explorer 8 users.
Download Internet Explorer 8 Performance Whitepaper
And if you are new to Internet Explorer 8, you can download this free browser from Microsoft: