Configuring page speed automatic is done by editting text files named
iiswebspeed.config. There is a configuration file located in the install directory. This file defines the root configuration which is inherited into all websites that have the module enabled.
The page speed module will also check for a files named iiswebspeed.config in the root of websites that have the IISpeed module enabled for website-specific configuration. The website specific configuration will inherit the root settings. You can disable IISpeed for a website by renaming iiswebspeed.config to something else.
View pagespeed configuration examples
PageSpeed Configuration and Tuning
Recommended reading for setting up PageSpeed optimization in detail