There are a few different things you can do to optimize the performance of your Drupal installation.
1. First, enable Drupal’s caching system. You can do this by going to Administer -> Site Configuration -> Performance. Here, change the values for Caching Mode to Normal and Block Cache to Enabled. Once changed, click the Save Configuration button at the bottom.
2. Next, you will want to disable all inactive modules/blocks on your site.To do this, go to Administer -> Site Building -> Modules (or Blocks). Deselect all modules/blocks your site is not currently using in the Enabled column. When finished, click the Save Configuration button at the bottom.
3. Finally, you will want to optimize your site’s MySQL database. To do this, log in to your database with PhpMyAdmin. Click on your database name to the left and it will display a list of the tables on the right.
4. At the bottom of the tables list, select the Check All link and then from the With Selected drop down box, select Optimize Table.
After the optimization completes, the MySQL requests will be faster in searching tables and will result in better performance for your website.