Right click > NVIDIA Control Panel > Manage 3D settings > Program settings (in case you haven't already added Payday 2, do it by using the "add" button and browising the exe file).

Once you see Payday 2's settings, scroll down a little bit untill you find:
"Maximum pre-rendered frames" and switch it to "1".
"Multi display/mixed-GPU acceleration" and switch it to "Single display performance mode".
"Power management mode" and switch it "Prefer maximum performance".

Now run Payday 2 and see if it works!

In case you still having some small stuttering, you can turn on v-sync in game and set the shadow quality to low.

Credits to my buddy Nivaal for helping me with that stuttering fix (works in Battlefield 4 too)

That's it for now, hope it worked for you =]