Thanks for the info. For everybody, who wants to use it with Arch Linux, the following link should give a good overview:

https://wiki.archlinux.org/index.php/Improving_performance#Z...

If you want to use the systemd solution you can do it like:

  pacman -S systemd-swap
  vim /etc/systemd/swap.conf   # disable zswap, enable zram
  systemctl start systemd-swap.service
  systemctl enable systemd-swap.service