I’m on an GeForce 9400m (mbp’09) using the nvidia driver. It’s working fine. For installing the driver check:
[HowTo] get legacy 340xx NVIDIA drivers back - #18 by omano .
The only issue right now was introduced with a recent update to pamac-manager that requires, if I remember correctly, OpenGl 3 that the card can’t provide. Installing pamac-gtk3 fixes that.