Having an .htaccess file is a pain regarding performances. Apache needs to read it on every single request (the page, every image, CSS files, JS files, etc.).
It is strongly recommended to move rules defined in Drupal .htaccess file in your Apache global configuration or in your vhost configuration file. This way all rules are only loaded 1 time, during Apache start.
To achieve this, just copy/paste your .htaccess content in your Apache server configuration file and don't forget to surround it by the directory where your Drupal install resides.
Note that we added AllowOverride None to prevent Drupal .htaccess to be read by Apache.
Check for syntaxe error:
$ apachectl configtest
And restart Apache:
$ apachectl restart
Note that if you are on Plesk, you must use the following command before restarting Apache:
$ /usr/local/psa/admin/sbin/websrvmng -u --vhost-name=example.com