Several users have reported significantly slower performance under Internet Explorer 8, particularly when the browser is first launched or when navigating to new pages. Delays of up to 30 seconds or more have been reported.
The problem, in most cases, is the presence of IE restricted sites and enhanced security configuration zones, which are generally created automatically by spyware removal software, such as Spybot and IESpyAd. Traditionally, the presence of these entries has been hugely beneficial, offering protection against malicious software. However, Internet Explorer 8 includes new security measures that may obviate the need for these entries, and the browser can suffer a tremendous speed hit in their presence.
The fastest and easiest way to remove these entries and dramatically increase Internet Explorer 8′s speed is to use the DelDomains package. Right click on this link and save the file to your desktop. Next, right-click on the downloaded file (DelDomains.inf) and select “Install.” The package will remove all Internet Explorer restricted sites, enhanced security configuration zones and trusted sites.
Alternatively, or in addition to the above fix, you can try registering actxprxy.dll, a process that has improved Internet Explorer 8′s performance for a handful of users.
Click the Start button then search for “CMD.” Right-click cmd.exe and select “Run as Administrator,” then type regsvr32 actxprxy.dll and press return. Quit then re-launch Internet Explorer 8 and check for improved performance.