First of all, make sure your system can run GTA 5 minimum and that your gpu has a good amount of memory (1GB/2GB VRAM)
Then, head to your desktop and right click.
Now, click on the NVIDIA Control Panel
Then, when you have the control panel up, head to 3D Settings > manage 3D Settings.
This is what you should currently be seeing
Now click on Program Settings, and then click on the bar to select a application, select GTA5.exe
When you are onto that, scroll down to the following.
Power Management Mode > Prefer Maximum Performance
If you have a Dual/Quad or more CPU - Threaded Optimisation > On
If you have 1GB to 2GB VRAM - Triple Buffering > On
High End Systems: Adaptive
Low End Systems: Adaptive (half refresh rate)
Then Apply the settings, screen may freeze for a second, this is normal.
Then close down NVIDIA Control Panel
Start up GTA V and watch the FPS difference (difference may vary between systems)
My Specs and FPS
Core 2 Quad Q8200 @ 2.33ghz
NVIDIA Geforce GT 740 2GB DDR3
6GB DDR2 333mhz
FPS Before - City 15/20fps. Countryside 25/30fps
FPS After - City 30-40fps. Countryside 50/60fps.
I hope I have helped many users with FPS issues to get their game to the speedy game they want!
Please leave a comment or PM if there is anything else in the NVIDIA Control Panel that I have missed!