Horrible Report Rendering Performance

Hello! We are having a strange problem with Reporting Services 2005. Our RS server is located in a DMZ with the supporting RS database housed in our internal network. We have a batch of reports that perform well when rendering to browsers in our internal network. However, when accessing these same reports externally, the reports take a very long time to render. The difference between internal vs. external is huge; we are looking at maybe a minute tops to render the report from an internal browser vs. 10-15 minutes from an external client browser. The website and reports are setup for anonymous access, so it shouldnt be an authentication problem.

The RS execution log doesnt indicate much difference between the two. The data retrieval does take a little longer (only a second or two), according to the log, for an external request. But still, the times recorded in the Execution Log dont match at all what we are experiencing for external requests.

The various logs, both for reporting services and IIS arent picking up any anomalies either and Im at my wits end as to what else I can use to try and troubleshoot this problem. Has anyone seen this behavior before, or have any ideas what might shed some light on this?