Current server: 
Debian
8-core 2.4Ghz
16GB RAM

$  dpkg -l | grep php
rc  libapache2-mod-php5                5.6.28-1~dotdeb+7.1              amd64        server-side, HTML-embedded scripting language (Apache 2 module)
rc  php-apc                            3.1.13-1                         amd64        APC (Alternative PHP Cache) module for PHP 5
ii  php5                               5.6.40-1~dotdeb+7.1              all          server-side, HTML-embedded scripting language (metapackage)
ii  php5-cli                           5.6.40-1~dotdeb+7.1              amd64        command-line interpreter for the php5 scripting language
ii  php5-common                        5.6.40-1~dotdeb+7.1              amd64        Common files for packages built from the php5 source
ii  php5-fpm                           5.6.40-1~dotdeb+7.1              amd64        server-side, HTML-embedded scripting language (FPM-CGI binary)
ii  php5-gd                            5.6.40-1~dotdeb+7.1              amd64        GD module for php5
ii  php5-imagick                       1:3.1.2-2~dotdeb+7.1             amd64        Provides a wrapper to the ImageMagick library


$ dpkg -l |grep apache
ii  apache2                            2.2.22-13+deb7u13                amd64        Apache HTTP Server metapackage
ii  apache2-mpm-worker                 2.2.22-13+deb7u13                amd64        Apache HTTP Server - high speed threaded model
ii  apache2-utils                      2.2.22-13+deb7u13                amd64        utility programs for webservers
ii  apache2.2-bin                      2.2.22-13+deb7u13                amd64        Apache HTTP Server common binary files
ii  apache2.2-common                   2.2.22-13+deb7u13                amd64        Apache HTTP Server common files
ii  libapache2-mod-fastcgi             2.4.7~0910052141-1               amd64        Apache 2 FastCGI module for long-running CGI scripts
rc  libapache2-mod-php5                5.6.28-1~dotdeb+7.1              amd64        server-side, HTML-embedded scripting language (Apache 2 module)


Configuration for Cronjob
gif.php should run every 1 minute to generate the .gif file.

$ crontab -e

*/1 * * * * php /var/www/o2/default/htdocs/o2aktionsserver.de/countdown-samsung-2021/gif.php >> /dev/null 2>&1