Recording on Photo Booth is freezing/running slow with Mac OS Sierra 10.12.3, what should I do?

Recording on Photo Booth is freezing/running slow since I updated my MacBook Pro mid2010 to the OS Sierra 10.12.3 (which, by the way, I was asked to by the App Store): WHAT CAN I DO in order to FIX this problem?

(PS: I'm afraid it is not only Photo Booth that is running slow now.)

Overview of my MacBook Pro:

- MacBook Pro (13-inch, Mid 2010)

- Processor 2,4 GHz Intel Core 2 Duo

- Memory 4 GB 1067 MHz DDR3

- Graphics NVIDIA GeForce 320M 256 MB

Thank you all,

Bruno