Optimizing Drupal Hosting / Drupal Optimization Guide
This is a quick guide on a few things to optimize to increase the speed of your Drupal installation:
1. Uninstall uneeded modules.
2. Remove unnecessary content
3. Install a PHP Accelerator (i.e. eaccelerator, xcache, etc). This will require root access to your server. A PHP accelerator will usually cache frequently accessed files, and will usually greatly improve server performance.
4. Analyse database queries, and look for slow queries. Create indexes for your Drupal database if required.
5. Install and configure memcached. Details can be found here: http://drupal.org/node/44220
6. Install advanced cache module, and apply requested patches
7. In admin/settings/performance change the Caching Mode to Normal
8. In admin/settings/performance change “Aggregate and compress CSS files” to Enabled
9. Install and Configure QueryCache module
10. Set HTTP headers cache options to optimal values
11. Use Xdebug too find PHP code bottle necksand then optimize them