---
title: "How to enable FSR4 with OptiScaler | OptiScaler"
description: "FSR4 depends on the selected output path, GPU capability, driver or SDK behavior, and game compatibility. Enable it in the overlay, then verify it is not a fallback."
canonical: https://optiscaler.ink/how-to/how-to-enable-fsr4
updated: 2026-10-18
---

# How to enable FSR4 with OptiScaler

FSR4 depends on the selected output path, GPU capability, driver or SDK behavior, and game compatibility. Enable it in the overlay, then verify it is not a fallback.

## Facts (2026-10-18)

- **Version:** OptiScaler 0.9.4 (reference build, July 2026)
- **APIs:** DirectX 11, DirectX 12, Vulkan
- **Upscalers:** DLSS, FSR and XeSS inputs/outputs where compatible
- **Frame generation:** Experimental OptiFG (DirectX 12)
- **Overlay:** Insert key
- **Install:** ZIP extracted next to the main game executable
- **Platform:** Windows; Linux via Proton/Wine varies
- **Site:** Independent guide — not the official project site

## In short

FSR4 depends on the selected output path, GPU capability, driver or SDK behavior, and game compatibility. Enable it in the overlay, then verify it is not a fallback.

## Steps

1. Install OptiScaler and open the overlay with Insert.

2. Select the FSR4 output where it is offered.

3. Launch a test scene.

4. Verify with the status/watermark indicator — see [how to check FSR4 is active](https://optiscaler.ink/how-to/how-to-check-fsr4-is-active).

## Facts that do not change

Reference build is OptiScaler 0.9.4. Install is a ZIP next to the main game executable; the overlay opens with Insert. Avoid online or anti-cheat protected games, and test offline first.

## FAQ

### What is OptiScaler?

OptiScaler is a community tool that can intercept supported in-game upscaler calls and redirect them to another supported upscaling backend, with additional tuning options.

### How does OptiScaler work in a game?

The game exposes an input upscaler, OptiScaler sits between the game and the selected output backend, and the chosen output handles the final upscaling path where compatibility allows.

### Does OptiScaler support DirectX 11?

Yes, DirectX 11 is supported, although the available output methods and behavior can differ from DirectX 12.

### Does OptiScaler support DirectX 12?

Yes. DirectX 12 has broad support and is also the API used by experimental OptiFG functionality.

## Related

- [OptiScaler how-to: install, overlay, FSR4 and fixes](https://optiscaler.ink/how-to)
- [OptiScaler FAQ: the official 20 questions, answered](https://optiscaler.ink/faq)
- [How to install OptiScaler](https://optiscaler.ink/how-to/how-to-install-optiscaler)
- [How to open the OptiScaler overlay with Insert](https://optiscaler.ink/how-to/how-to-open-the-overlay)
- [How to fix the OptiScaler overlay not showing](https://optiscaler.ink/how-to/how-to-fix-overlay-not-showing)

## Download

ZIP next to the game executable: [Download OptiScaler](https://optiscaler.ink/download)

Markdown mirror: https://optiscaler.ink/how-to/how-to-enable-fsr4.md