SCSKiller

Shader Compilation Stutter Killer. SCSKiller compiles your games' shaders into your GPU driver's cache before you play, so the game doesn't stop to compile them mid-game. Free and open source, for Windows.

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[!WARNING] The only official downloads are this repository's Releases. See official links for the accounts and sites that belong to SCSKiller.

A game that meets a new effect has the GPU driver compile its shader on the spot, and the frame waits: that's shader compilation stutter. SCSKiller reads the shaders a game ships with, works out the pipelines it will build, and compiles them into the driver's cache ahead of time, in its own process with the game closed.

Results

About 5 minutes of play per game, from a cold driver cache and after compiling with SCSKiller. A stutter is a shader compile the game waited 20 ms or more for.

Game	GPU	Measurement	Cold	With SCSKiller
Final Fantasy VII Rebirth	NVIDIA RTX 5090	Stutters (≥ 20 ms)	19	0
		Worst stall	76 ms	5 ms
	AMD Ryzen AI Max+ 395 (Strix Halo)	Stutters (≥ 20 ms)	162	0
		Worst stall	291 ms	7 ms
Silent Hill: Townfall	NVIDIA RTX 5090	Stutters (≥ 20 ms)	24	0
		Worst stall	347 ms	8 ms
Hogwarts Legacy	NVIDIA RTX 5090	Stutters (≥ 20 ms)	1,014	87
		Worst stall	2,400 ms	100 ms
	AMD Ryzen AI Max+ 395 (Strix Halo)	Stutters (≥ 20 ms)	27,743	206
		Worst stall	2,146 ms	104 ms
Tiny Tina's Wonderlands	NVIDIA RTX 5090	Stutters (≥ 20 ms)	583	0
		Worst stall	315 ms	13 ms
Star Wars Jedi: Survivor	NVIDIA RTX 5090	Stutters (≥ 20 ms)	9,038	11

Measured with SCSKiller's recorder. Your numbers depend on the game, GPU and driver. SCSKiller fixes shader compilation stutter only, not traversal or streaming stutter, and a shader it couldn't find or record can still compile in game.

Features

• NVIDIA and AMD, DirectX 12 games, and DirectX 11 games on NVIDIA.
• Finds your games in Steam, Epic Games, EA app, GOG, Ubisoft Connect, Xbox (PC), Battle.net, PURPLE, HoYoPlay, Gaijin and the Riot Client, plus games you add yourself.
• Puts games known to stutter on top, with the reason, and marks games whose engine prepares its shaders itself.
• Compiles again after a driver update, which clears the shader cache, on its own if you let it.
• Optional recorder for games whose pipelines its files don't give: play a few minutes with it on, then compile. It also records alongside a mod that replaces shaders.
• Frame times per session: with the recorder on, a game's page graphs your last session and marks shader stutters apart from other hitches. They stay on your PC.
• Play button that starts the game through its store.
• Community shader hash database for Patreon supporters: other players' recordings, so your games are covered without recording them first. Sharing yours is opt-in, anonymous and hash-only.
• Leaves anti-cheat games alone beyond reading their files: no launching, no injecting, no recorder, except in a session you allow per game and confirm every launch, at your own risk: without EasyAntiCheat for ELDEN RING and ARMORED CORE VI, or in games with anti-cheat once you turn on "Allow the recorder in games with anti-cheat (at your own risk)".

Install

Requirement
OS	Windows 10 (version 2004) or 11, 64-bit
GPU	NVIDIA or AMD
Games	DirectX 12, DirectX 11 on NVIDIA

Intel GPUs aren't supported yet: I don't have one to test on. If you'd like to sponsor an Intel Arc GPU, get in touch at contact@scskiller.com.

Download SCSKiller-Setup.exe from Releases and run it. It installs for your user only, needs no admin rights and updates itself.

Or unzip SCSKiller-<version>-Portable.zip to any folder you can write to and run SCSKiller.exe. It updates itself too, and keeps its settings and data in a data folder beside the exe. Turn recording off for your games before you delete the folder, so the recorder leaves the game folders.

[!IMPORTANT] Releases aren't code-signed yet, so the first run will probably show SmartScreen's "Windows protected your PC". Click More info, then Run anyway. Updates never show it. Signing through the SignPath Foundation is in progress. To check a download, compare its SHA-256 with the one in the release notes (PowerShell: Get-FileHash <file>). Smart App Control (Windows 11) blocks unsigned apps outright: if it's on, wait for a signed release.

How to use it

1. Open SCSKiller. It finds your games and the shaders they ship with.
2. Queue games and press Compile. "Add all recommended" is a good start. Keep the game closed while it compiles.
3. Play, from your store or with the Play button. SCSKiller can be closed. Left open, it checks that the compile reached the cache the game really uses, and with the recorder on, the game's page shows your session's frame times and anything that still compiled.

If a game needs a recording, turn on Record, play it for a few minutes, then compile it.

FAQ

Can I get banned? SCSKiller only reads the files of games with anti-cheat and adds its recorder to them only in a session you allow and confirm (next question). Its anti-cheat check can still miss a game, so you use SCSKiller at your own risk, and its authors are not responsible for bans, crashes or lost data.

Is it safe with anti-cheat games? Outside a session SCSKiller never launches them, injects into them or gives them the recorder. It only reads their files. A session is allowed per game, confirmed every launch, and at your own risk. The offline session for ELDEN RING and ARMORED CORE VI runs them offline without EasyAntiCheat when their exe is started directly: Steam must be running (offline mode is fine), and SCSKiller adds d3d12.dll, scskiller.ini and steam_appid.txt to the game's folder and starts the exe itself. With "Allow the recorder in games with anti-cheat (at your own risk)" on in Settings, any other supported game can run a session too: SCSKiller starts the game as usual, with d3d12.dll and scskiller.ini in its folder. Games with anti-cheat can treat the recorder as cheating and ban your account, during the session or later. No game is known to be safe. Enabling the recorder in these games is at your own risk, and SCSKiller isn't responsible for bans. Bans from it are not support issues. In both kinds the recorder records only that process. When the game exits, SCSKiller takes those files out again (each only while it is still the file it added) and keeps the recording and the session's frame times, at the next logon or start if SCSKiller was closed or the PC crashed. If those files are still there when you start the game online, you could be banned. Don't uninstall SCSKiller while the game runs.

What does it write, and where? Settings and per-game plans go in %LOCALAPPDATA%\SCSKiller\ (the data folder of a portable copy), and the compiled pipelines go in your driver's own shader cache. Game files are never modified. The optional recorder adds d3d12.dll and scskiller.ini to the folder of a game you turn it on for, and turning it off removes exactly those files. It never goes into a game with anti-cheat, and comes out the moment SCSKiller finds anti-cheat: when it scans, when the game exits or updates, and every 2 minutes while it runs. scskiller.ini names the game's exe as it was when SCSKiller last found no anti-cheat in its folders, and a game records only while its exe is still that one and no anti-cheat is next to it. Uninstalling SCSKiller removes these files and the recordings from every game folder, and a scan removes them from a game Steam uninstalled.

Does it touch my drivers or their settings? No. It compiles through DirectX, as the game would.

Do I need an account? No. Everything the app does on your PC is free. Signing in with Patreon adds the supporter features.

My game isn't detected, or something broke. Open an issue with the bug or game request template.

Support the project

The app is free and stays free. Patreon pays for the servers behind the community database. Sign in with Patreon in Settings to unlock your tier.

Tier	You get
Patreon supporter	The community shader hash database, and beta builds
Patreon backer	All of that, plus alpha builds and priority on game requests

Build from source

Visual Studio 2022 (C++ desktop workload with CMake) and the .NET 10 SDK:

cmake -S proxy -B proxy/build -A x64
cmake --build proxy/build --config Release
dotnet build SCSKiller.slnx -c Release

build/publish.ps1 builds the distribution into dist\. Design: ARCHITECTURE.md. Contributing: CONTRIBUTING.md. Changes: CHANGELOG.md. Security issues go through SECURITY.md, never a public issue.

Official links

• GitHub: https://github.com/BlueHeisenberg/SCSKiller
• Website: https://scskiller.com
• Patreon: https://www.patreon.com/SCSKiller
• Discord: https://discord.gg/st7C4yCTcN
• X: https://x.com/SCSKiller

Anything else claiming to be SCSKiller isn't. Please report it.

Licence

GPL-3.0-or-later (LICENSE), with an additional permission for Oodle, the Windows App SDK and graphics driver libraries (LICENSE-EXCEPTION.txt). Third-party components: THIRD-PARTY-NOTICES.md. Code signing: CODE_SIGNING_POLICY.md.

Not affiliated with any GPU maker, engine maker or game publisher. All product names are trademarks of their owners.

Forks

Forks are welcome under the licence. Please give yours its own name, say it's unofficial and based on SCSKiller, and keep the SCSKiller copyright notices. The measurements and screenshots in this README are SCSKiller's own, so please don't present them as a fork's.

Official builds come only from this repository's Releases page. A fork's builds, bugs and anti-cheat behaviour are its author's: SCSKiller keeps its recorder out of anti-cheat games except in a session the user confirms, and can't vouch for a fork that changes that.

Improvements are always welcome back here as pull requests. Fixes, games and ideas from forks make SCSKiller better for everyone.