The driver are the same for all of your cards. You can also enable your physx in the nVidia controll panel. There are only a few games that will benefit from Physx and I mean a few.
Most of the time on games that don't support Physx you will have a performance drop. So sometimes it isn't worth have a Physx at all. I will link you to a Gforce web site with a list of games that support Physx.
You might not want to use it the Physx but it is up to you and again the drivers are the same for all of your cards. Hope this helps and good luck to you.