Why the Graphics Card on my MacBook Pro is always on "High perf." status? After I've installed Nvidia Cuda Drivers the Activity Monitor show that Graphics Card is always on High Perf. status. No application that "Requires High Perf GPU" is running and the battery goes down quickly, very quickly. 

Any idea how to solve that expensive problem?
Are you using an external monitor? MacBook start using discrete card if external screen is connected.