Slow horizontal movement.
 

So I am at my friends house playing on his setup.. The biggest problem is that when I am in 1st person(or scrolled out into 3rd person) When I right click to look around it moves very slow HORIZONTALLY.

Only horizontally though, and no other time does it do this. Even if I fit F9 to another camera and move the camera with right-click.. it moves at a normal speed.. Wtf mate?

Anyway I hope someone has the answer.. but likely few will view.. and no one will ever respond to this thread.

Try adjusting your ingame max frame rate, changing down from 100 to something closer to your VDU's frame refresh.

Edit: Under your options, Display tab, the settings is called Max frames per second.

Thanks, this advice did the trick!