I have not seen any other posts (or posted bugs) about such behavior.

No-charge support for Internet Explorer 8 installation, set-up and usage
(only) is available via the phone based on your locale through 31 December
2009. Customers must be running Windows XP or Windows Vista in a non-domain
environment.
=> US & CA Residents: 1-866-234-6020
=> Other locales: https://support.microsoft.com/oas/de...px?&prid=13043

My personal recommendations include:

=> Install IE8 manually, not via Windows Update/Automatic Updates!!

=> Uninstall all third-party toolbars (e.g., Google; Yahoo; Windows Live)
and third-party Windows Themes before installing IE8.

=> Close all open applications (i.e., anything with a taskbar icon) before
installing or uninstalling IE8.

=> I would strongly recommend disabling your anti-virus application and any
anti-spyware application's "system protections" (other than Defender's)
before installing (or uninstalling) an IE upgrade. If you're running a
third-party firewall, I would recommend disabling it and then enabling the
Windows Firewall before installing (or uninstalling) an IE upgrade.

=> Create a Restore Point manually before installing IE8. [Do NOT use
System Restore to remove/uninstall IE8; instead, see
http://support.microsoft.com/kb/957700. Then use the Restore Point prior to
reinstalling IE8 per these recommendations. Norton users will need to see
http://bertk.mvps.org/html/symantecdoc1.html.]

=> Reboot twice after installing or uninstalling IE8.

=> For best chance of success with IE8, make certain that your anti-virus
application, any anti-spyware applications (other than Defender), and your
third-party firewall (if any) are supported in IE8 Final before you decide
install it.
--
~Robear Dyer (PA Bear)
MS MVP-IE, Mail, Security, Windows Client - since 2002


bargz wrote:
> I have Windows XP SP3, and I decided to install Internet Explorer 8 last
> week. It installed fine, and I used it for a week, but my desktop UI
> speed
> had become NOTICEABLY sluggish: when I move windows around, there would be
> a
> white "lag" behind them, similar to turning on "mouse trails" for your
> cursor. It acted like I had disabled video acceleration. Also, YouTube
> videos were jittery and my CPU utilization was very high while watching.
>
> Thinking it may have been outdated NVidia drivers, I downloaded and
> installed the latest release from NVidia's web site, but the situation did
> not improve.
>
> I've searched the web and the newsgroups and cannot find anyone with a
> similar problem; I found some people complained about sluggish WEB PAGES
> with IE8, but my issue is not that web pages are slow to load, but
> specifically it's a problem with my GUI rendering speed.
>
> Anyway, this morning I uninstalled IE8, rebooted, and now my GUI speed is
> back to normal (fast) -- I can move windows around without trails -- so it
> is obviously something with Internet Explorer 8.
>
> My system specs:
> Dell 400SC
> Pentium-4 HT 2.8GHz single core
> 3 GB memory
> NVidia GeForce 7600 GS 512MB AGP 8X, driver version 185.85
> Dual LCD monitors
> Windows XP SP3 with all high-priority updates
>
> Thoughts? Anyone?