Open NVIDIA Control Panel > Manage 3D Settings > Power management mode . Change this to Prefer maximum performance .
Download Display Driver Uninstaller (DDU) to completely wipe your old drivers in Safe Mode.
Check for "Max FPS" sliders in the game menu and set them to unlimited.
Ensure your GPU is in the topmost PCIe slot (usually the x16 slot) for maximum bandwidth.
To help me give you more specific advice, could you tell me: What are your (CPU, GPU, and RAM)? Which specific games are giving you trouble? What resolution (1080p, 1440p, etc.) are you playing at?