In addition to Robert's suggestion, you might also want to try this:

http://support.microsoft.com/default.aspx?scid=kb;en-us;320909


>>hi all!
>>
>>we do have a aspx-webform which contains a treeview (microsoft.web.ui.webcontrols - version 1.0.2.226).
>>the problem is that this treeview takes a long time for loading, 46 seconds according to the trace-function when we call the site containing this element.
>>the data is provided via an xml-file (database = sql-server) which is converted using a xslt-file
>>
>>can anybody help us???
>
>You can try to use some JScript TreeView control
>from http://aspalliance.aspin.com/home/components/navigator/treeview?cob=aspalliance