vbseo.com site performance issue

Hello
I have a serious issue at vbseo.com when viewing forum.php using IE8. Every time I refresh the page the browser hangs for 30 seconds and is unresponsive. Sometimes the website will grey out and a no response error will be displayed. After 30 seconds the browser becomes responsive again. I've encountered this problem since at least December. Anyone have an idea or suggestion?

I'm sorry for the spelling errors. Vbulletin4 does not support google's toolbar spellcheck.

This does not occur on other vb4 websites with vbseo that I've visited. ...

I just discovered that I do not see this problem in IE8 when using the compatibility view feature.

We've had various mixed reports of this, but so far we have not been able to reproduce it. I toggeled the site with the compatiblioty option several times and it loaded the same each way.