Thanks for your response. Unfortunately it was still not very clear for me since SQL cursors is a rather new concept for me. I did however find some resources that helped me further:

http://laravel.at.jeffsbox.eu/laravel-5-eloquent-builder-chunk-cursor

Which led me to:

https://en.wikipedia.org/wiki/Cursor_(databases)

So now it is much more clear for me. So using cursors decreases memory usage on the client but can increase network traffic (network round trip) and increased memory usage on the database server. And if you don't close your cursor when done it will leave a huge block of memory open until the session is closed. But still it will do a lot for application performance I think.

Thanks for pointing me in the right direction.

Lazy Collections