Below are some points to differentiate between the Joomla and Drupal:-
Joomla uses plugins components and modules while Drupal has a module only.
Joomla has lower technical curve while Drupal has high technical curve.
Joomla uses bootstrap while Drupal uses Smarty template.
Joomla is easier to install and configure as compared to Drupal.
Joomla is easier to develop custom functionality when compared with Drupal.
Joomla is good for E-Commerce type of sites but less powerful CMS as compared to Drupal.
Joomla response time is slower while Drupal has faster response time and load the page more quickly as compared to Joomla.
Joomla has strong social networking feature to perform community platform while Drupal has powerful taxonomy and ability to tag, categorize and organize complex content.
In case of caching Joomla has system cache plugin by default that improves the speed of page loading while Drupal has a free downloadable plugin called ('Pressflow') that perform caching and enhance the performance and scalability of you site.