I have an issue here at work where a user is using Reader 9.3.0 and she is able to successfully find an entry/data when using a 16,000 page pdf file (66 MB file) within seconds - the entry comes up after 5 seconds even when she starts at page 1. Another user that has the same version of Reader (9.3.0) is not having this success. When she starts the find option, the search starts at page 1 and just moves from there. It could take 45-60 minutes to get to the same point in the PDF that the other user gets to within seconds.
One thing that I did notice is that the user that has the quick search/find doesn't have the page numbers escalate one at a time; the search is run in the background and then it finds the data that she was looking for.
Both users have enable "enable fast find" selected with a cache size of 100 MB.