Amongs Google PageSpeed ranking factors is one regarding a Content Delivery Network, that wants to use subdomains or a CDN for distributing content. If you have basic DNS and HTML knowledge you can do these easy steps:
- add to your DNS Aliases (A records) with the name cache1.yourdomain.com and cache2.yourdomain.com in order to point to the same place as www.yourdomain.com
- edit your theme header.php file and change the adresses of the css and js files to cache1.yourdomain.com. do this with the plugins also.
- go to your media options in wordpress and put full URL path to files to cache2.yourdomain.com, as seen below:
That is all. This can be easily done using CDN rewrites or WP-Supercache after completing step one.