gSwitch allows you to choose which graphics card your MacBook pro can run, in order to prevent it from running the discrete graphics card if it is not necessary. You might be asking why you would want to do this. The discrete graphics card consumes significantly more power than an integrated one, which can cause battery drain. Apple has not yet fixed some problems with MacBooks that have buggy and glitchy graphics card drivers.
The software is free but it is donationware. To support development, please consider donating.
Version 1.9.7: