Is there a difference between "Clear cached data" button on the performance page and drush cc all? Is there a difference in what caching is cleared between

drush cc all


and

Admin &gt; Site Configuration &gt; Performance &gt; Clear cached data button


?
Short answer:  There is no significant difference.

Drupal:

function system_clear_cache_submit($form, &amp;$form_state) {
  drupal_flush_all_caches();
  drupal_set_message(t('Caches cleared.'));
}


Drush:

function drush_cache_clear_both() {
  drush_cache_clear_drush();
  if (drush_has_boostrapped(DRUSH_BOOTSTRAP_DRUPAL_FULL)) {
    drupal_flush_all_caches();
  }
}


Both end up calling drupal_flush_all_caches, which clears the standard Drupal caches, cached CSS/JS files, and everything declared by a hook_flush_caches.

drush_cache_clear_both is what is called by 'cc all'.  drush_cache_clear_drush clears some drush caches that have no effect on the Drupal site.