How to enable zram

sudo echo "zram" > /etc/modules-load.d/zram.conf
sudo echo "zram num_devices=4" > /etc/modprobe.d/zram.conf
Edit /etc/systemd/system/zram.service
add
[Unit]
Description=Swap with zram
After=multi-user.target

[Service]
Type=oneshot
RemainAfterExit=true
ExecStartPre=zramctl -f -s 2500MiB -a lz4
ExecStartPre=/sbin/mkswap /dev/zram0
ExecStart=/sbin/swapon /dev/zram0
ExecStop=/sbin/swapoff /dev/zram0

[Install]
WantedBy=multi-user.target

Save and close
Then sudo systemctl enable zram
And then add to /etc/sysctl.conf
vm.vfs_cache_pressure=500
vm.swappiness=100
vm.dirty_background_ratio=1
vm.dirty_ratio=50
Save and reboot.