Vice President of Autodesk Labs and inventor of DWF, Brian Mathews reports that: by default recent versions of AutoCAD publish DWF files in the background. This can double the time it takes to publish DWF files. The feature is helpful when publishing large numbers of DWF files, since you can continue to work in AutoCAD while publishing happens in the background; however, if you only have a few sheets to publish or want to maximize publish speed, you should disable background publishing. To change the setting go to the Tools > Options… menu, select the Plot and Publish tab, and uncheck Publishing.
AutoCAD provides users with an alternative: fast in front of your eyes or more slowly behind the scenes.