Improving WordPress Performance
There is a downside to WordPress: that it can be painfully slow when a site gets busy. To combat this, we strongly recommend that you install a plugin called WP Super Cache. When using WP Super Cache, WordPress pages are cached and stored in a static file for serving future requests directly from the file rather than building the page again from the content database. This hugely improves the responsiveness of the website.
Installing WP Super Cache
WordPress now comes with a handy plugin installation tool, which allows you to search their repository and install new plugins, straight from the dashboard. Hover your mouse cursor over the Plugins entry in the menu on the left-hand side of the dashboard, and choose the 'Add New' option. Type 'wp super cache' in the search field and then click on the 'Search Plugins' button. The WP Super Cache plugin should be the top entry. Click on the 'Install Now' link to install the plugin. Click 'OK' when asked if you are sure you want to install the plugin. Once the installation process has finished, click on the 'Activate Plugin' link.
You should already be in the settings menu, so from here, you can choose the 'WP Super Cache' entry. Change the Caching option from 'Caching Off' to 'Caching On' and then click on the 'Update Status' button. WP Super Cache should now be up and running. To verify that WP Super Cache is working correctly, go to a page on your WordPress site and view the page source code. This step varies for each web browser, but look for a tools, or web developer section, and then look for an option called page source. Once you have found this, go to the very bottom of the code and look for an entry similar to:
<!-- Dynamic page generated in 0.381 seconds. --> <!-- Cached page generated by WP-Super-Cache on 2012-07-26 16:46:04 -->
If you see something like this, then WP Super Cache is working just fine.
If your WordPress site is receiving a lot of traffic, it may be time to switch to using FastCGI. See this page for instructions.