Hello, I am having difficulty troubleshooting a slow performance issue.

I have Umbraco 4.0.2.1 installed on an XP machine and using ASP.NET 2.0.50727.

Browsing the actual website, performance is fine. And most of the admin site - for instance the sections on Media, Settings, Developer are fine too. But when going to the Content node and clicking on a page in the left side tree view, it is very slow for the content to appear in the main window.

This machine is meant to be a preview/testing site. The production site is running on a Server 2003 machine with the same Umbraco and ASP.NET versions. To create the test site, I backed up and restored the SQL database from the production box to this testing box. I also simply copied over all the files from the webroot, and modified the web.config connection string. I mention this because I wonder if something could be timing out or searching for a reference to something from the production site instance, I don't know.

I haven't upgraded to a newer Umbraco version because I was hoping to keep it the same version as the production site. (Which has fine performance, by the way).

I have tried deleting all the files in /data/systemUmbracoIndexDontDelete and then browsing to http://machinename/umbraco/reindex.aspx. That didn't help the issue.

Finally, I used Firefox with Firebug to see if that would help narrow it down. What I see is that everything returns quickly, in just a few milliseconds except one GET request takes 25+ seconds. That request is to a URL like

http://machinename/umbraco/plugins/tinymce3/tinymce3tinymceCompress.aspx?rnd=15785748-d98b-46ee-82d0-3be2fb324af7&module=gzipmodule&themes=umbraco&plugins=contextmenu,table,umbracomacro,paste,inlinepopups,media,umbracocss,advimage,advlink,noneditable&languages=en

I don't know what to try next. Thanks in advance for any advice.