Any solution to View PDF timing out in the OAF pages?

We're finding that the View PDF option in Buyer Work Center > Orders usually times out. One purchase order today with 130 line items took 8 minutes to run using PO Output For Communication. That is far too long for the OAF page to wait, and 130 lines is one of our smaller POs. Looking at the log, the GetPOXML()/POXMLGEN process took 6 minutes. Has anyone traced and tuned this process? If there is no solution for this we will need to disable the option and replace it with a call to the concurrent job and scheduler. Suggestions welcome. Thanks