With TMPFS you can dramatically improve the speed of mod_pagespeed and the webpages served by it. TMPFS will store/serve the optimized PageSpeed output directly from RAM!
To prepare for several upcoming articles on AskApache that are focused on optimizing Servers and Sites from a server admin level, here is an article to introduce the main tools that we will be using. These tools are used to optimize CPU time for each process using nice and renice, and other tools like ionice are used to optimize the Disk IO, or Disk speed / Disk traffic for each process. Then you can make sure your mysqld and httpd processes are always fast and prioritized.