This question already has an answer here:
It seems that they have the physical ability to run and yet we never see them doing this, even when quicker movements would more benefit the completion of their goals. To quickly stop an opponent from activating some release mechanism or complete some computer command procedure would seem a worthy reason to move more quickly yet they move zombie like no matter the situation or task at hand. Is there some reason that they only walk and not run when it would seem more appropriate to do so?
As an addition, there are multiple examples of 'former' Borg drones being able to run and/or move very quickly.