So, you need to make your Drupal-based site work faster. In this article I would show you a few tricks to do this.

• In the list of modules, disable all modules which are not used. Maybe you should sacrifice the statistics modules;
• Caching in Drupal decreases loading of database and significantly increases performance. While cache is essential for anonymous users only, we recommend you to enable cache because anonymous users are a great mass of site visitors;
• Disable using of mod_rewrite in .htaccess. URLs will be not so fine and short. But the most CMS don’t use short URLs;
• locale module has bad effect on site performance but usually you need localization. So, adapt it for working with gettext and view if your site performance increased. Or disable interface localization;
• Themes with XML-templates usually are slower than templates that used PHP only. Please view what is the default theme: if it is something like xtemplate, with XML- template, change theme. New theme should use PHP only (for example, chameleon);
• An important part of increasing of site performance is info about requests to database. Install devel, enable displaying of requests and view time of their performing. Some additional modules can create delays (or example, non-optimal SQL-requests). Usually there is no such problem in standard modules. Try to disable different modules (even standard ones) to and pay attention to time of page generating. At the same time:
  • Decrease number of documents (node), which are displayed on the home page by default (if node module is used for your home page).
  • Check table indexes in database.
  • Make total optimize of all tables (you can do it regularly).
• Use mod_gzip of Apache web-server – it compresses files which are passed to web-browser.
• Use caching of different types.
• Optimize PHP-code
• Optimize database structure
• Optimize settings of web-browser, database, PHP
• Replace pages generated with View module with your own code which will be faster.
• Decrease time of loading page (CSS and JS compression, optimization of images and HTML)