If you consider performance important, you really should use one of the many caching plugins to do page caching. Some good candidates to complement Autoptimize that way are e.g. WP Super Cache, HyperCache, Comet Cache or KeyCDN’s Cache Enabler.
We provide great Autoptimize Pro Support and Web Performance Optimization services, check out our offering on (http://autoptimize.com/)!
(Speed-surfing image under creative commons by LL Twistiti)
Page officielle : https://fr.wordpress.org/plugins/autoptimize/