The RAT gives absolute minimum, above a certain speed and with the nose gear up. Turbulence off the nose gear was a problem years ago, I don't know if that has been tackled with increased min speed or modified RAT.
The RAT is modified, visible on the RAT Door. The "old one" is flat and the "modified one" not.
But, the "old one" is working also with NLG down and it is stop working (if i'm remind me correct) with approx 90knots and then you don't really need hydraulic or electrical power. Then you will stop with the brake akku and evac with the emergency light and the slide raft