Actually it runs slowly in Firefox as well - 27.5 seconds when I tried it with Firebug.
Here is the graph:
As you see to load a small image like bg.gif or tabLeftOff.gif takes 4 seconds. This means a heavy loaded web server
or slow connection
I noticed that the combined web resources (Telerik.Web.UI.WebResource.axd requests) are not compressed.
The handler checks whether the requesting browser supports compression and if the Accept-Encoding http header contains "gzip" or "deflate". Could it be some
firewall issue? There is a known problem with some firewalls stripping the
Accept-encoding header. Please check this topic for details.
In addition you can check our Top Performance page.
the Telerik team