Magpie: Best config.json for FSR Scaling on Windowed Games

While most users change settings in the UI, editing the JSON directly allows you to fine-tune the Sharpness ($S$) and Scale Factor ($k$) beyond the default sliders.

File Path

Navigate to the directory where you extracted Magpie. The configuration for specific scaling models is usually stored here:

[Magpie Path]\Magpie\Local\ScaleModels.json

Technical Note: Always back up your original JSON before editing. In the 2026 builds, ensure “WinRT Capture” is selected in the UI as it provides the lowest latency for windowed capture.

Optimized “FSR + CAS Hybrid” JSON Block

Add this entry to your ScaleModels.json list. This configuration runs FSR for the initial upscale and then applies a lightweight CAS pass to restore edge clarity.

Parameter	Recommended Value	Technical Purpose
"sharpness" (FSR)	0.3	Controls the initial FSR edge reconstruction.
"sharpness" (CAS)	0.4	The Clarity King. Adds high-frequency detail after the upscale.
"scale"	[-1, -1]	Automatically scales to your current window/monitor resolution.

{
  "name": "FSR_HighSpeed_2026",
  "model": [
    {
      "module": "FFX",
      "effect": "FSR",
      "scale": [-1, -1],
      "sharpness": 0.3
    },
    {
      "module": "FFX",
      "effect": "CAS",
      "sharpness": 0.4
    }
  ]
}

HowTo: Engineering Maximum Clarity in Windowed Mode

Follow these GameEngineer.net technical steps to ensure FSR performs optimally:

1. The 3D Game Mode Toggle: In the Magpie UI, always enable 3D Game Mode. This optimizes cursor behavior and prevents the Windows taskbar from interrupting the scaling process, which is critical for titles like Elden Ring or Cyberpunk 2077 in windowed mode.
2. DPI Scaling Override: Right-click Magpie.exe > Properties > Compatibility. Set High DPI scaling override to Application. If Windows tries to scale Magpie itself, you will end up with a “double-scaled” blurry image.
3. Source Resolution Logic: For a 1440p monitor, run your game in windowed mode at 960×540 (for perfect integer alignment) or 1280×720. FSR performs best when the scale factor is exactly $2.0 \times$ or $1.5 \times$.
4. Disable In-Game Sharpening: If your game has a built-in sharpening slider (like TAA Sharpen), set it to 0. Let Magpie handle the sharpening; stacking two different sharpening algorithms ($S_1 + S_2$) creates “halos” around text and UI elements.
5. DirectFlip Optimization: If you experience stuttering, toggle “Disable DirectFlip” in the Magpie settings. DirectFlip is meant to reduce latency, but in certain DX11 windowed games, it can cause the frame delivery to become erratic.

Technical Explanation: FSR Spatial Upscaling vs. CAS

Magpie’s FSR implementation uses a Spatial Upscaling algorithm. Unlike DLSS, it doesn’t use motion vectors. Instead, it identifies edges using a gradient analysis ($G_x, G_y$). By adding a CAS (Contrast Adaptive Sharpening) pass in the JSON, we apply a local contrast enhancement that focuses on the “inner” parts of the textures.

Mathematically, while FSR handles the reconstruction ($R$), CAS handles the texture definition ($D$). By keeping FSR sharpness low (0.3) and CAS moderate (0.4), we achieve a result where $R + D$ equals an image that looks “Native-ish” without the harsh white edges associated with over-sharpening. This reduces the GPU compute time by approximately $1\text{–}1.5\text{ms}$ compared to using more complex algorithms like Anime4K.