This topic has a very clear intent: the user wants more FPS right now. Fortnite Performance Mode is one of the most direct answers because it is designed to reduce visual load and improve smoothness on PC.
Epic explains that Performance Mode can help players dealing with low FPS. The idea is to trade visual quality for less load on CPU, GPU and memory.
Inside Fortnite, open Settings, go to the Video tab and look for Rendering Mode. Choose Performance, apply the changes and restart the game.
If you also uncheck High Resolution Textures from the Epic launcher, you can save more than 15 GB of storage and reduce the total install size.
If you play on modest hardware, want stability, or need the highest possible smoothness for competitive play, this is one of the first options worth trying.
Visual quality and performance always trade off against each other. The goal of Performance Mode is to make the game smoother, not prettier.
If you want a more personalized configuration for your hardware, RapidFPS optimizer helps you decide what to change based on your real PC, not just the game itself.