We have a Windows 2008 R2 web server running our web app on IIS and when running a particular page which generates a PDF (using Active Reports https://activereports.grapecity.com/) it takes between 1 and 2 minutes to generate the PDF document. The same application running on different servers does not experience the same issue, and also executing the same report from a console app on the same server completes in 2-3 seconds.
When this issue happens, I can see using IIS Worker Processes and then Resource Monitor->Analyze Wait Chain that the w3wp.exe process is waiting on splwow64.exe
I'm not sure how to proceed next. I've used procmon from SysInternals to watch the splwow64.exe process when this is happening but I can't see any out of the ordinary registry or file activity.
Is there anywhere else I can look to understand what might be causing the hang?