This is no hacks or anything, just general system tweaks you can use to improve game performance in general, especially if your CPU isn't too strong.

NVIDIA control panel (no clue about AMD cards, since I don't use one)

- POWER MANAGEMENT MODE: Open the NVIDIA control panel (right click on Desktop and click it), choose "manage 3D Settings", scroll down to "Power management mode" and set it to "Prefer maximum performance". Don't close the panel just yet...

- V-SYNC VIA DRIVER: Still...

General advice for performance for PC