Even though I prefer using the free 1MB Foxit Reader which allows editing text in PDF files, here’s a tip from DWTIPS to speed up PDF file loading in Adobe’s own 20 MB monster reader.

1) Install the latest version of Adobe Acrobat - you can get it here
2) Browse to the plugins folder: C:\Program Files\Adobe\Acrobat 7.0\Reader\plug_ins
3) Create a new folder named Optional
4) Move all files from the plug_ins folder to Optional, except EWH32.api, print*.api, and Search*.api

From DWTIPS