Modprobe and /etc/modules

[Husse]

Well modprobe is not persistent but putting it in /etc/modules is....
However if modprobe is persistent/not persistent is blatantly lacking from normal documentation
Edit
I should have noted that some modules that are loaded (with modprobe) in themselves have a piece of code to make them autostart at boot, so they don't need the help of /etc/modules

[Husse]

Probably safest to just add to /etc/modules all the time then.

Well you might end up with a "double load"
Don't do it and check if it's loaded - if not add to /etc/modules (and modprobe for the present session)
I should alos have noted that modprobe loads into RAM

[Husse]

Or it could be that laptops have much slower hard disks - there are very few lappys with a decent hdd