Report Slow Down

We have a report that used to produce a 1000+ page pdf in about 2 minutes. It has gone to producing a 200+ page report in about the same amount of time. No change to the data, database, report or environment, it just suddenly slowed down and nothing seems to be able to make it go back to decent performance on large record sets.
Server reboots don't help, any ideas or thoughts would be appreciated.