Afterglow

Free, open-source overclocking, undervolting, fan control and monitoring for NVIDIA RTX graphics cards.
Intel Arc support in beta. No kernel driver, no telemetry, no account.

Download for Windows · All features · What's new

_{The dashboard after ten minutes of ordinary desktop use on an RTX 5090.}

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What it does

Shows you what your card is doing. Clock speeds, temperatures (including memory junction on RTX 50 cards, which most tools can't read), power draw, voltage, fan speeds and load, with ten minutes of history behind every number. When the card slows itself down, Afterglow tells you why in plain words ("the board hit its power limit") and how many degrees you have left before it starts throttling.

Overclocks and undervolts, safely. Every slider is limited to the range the driver says is legal for your exact card, and each change is read back to confirm it actually took (NVIDIA's clock lock is the exception: the driver can't report it, so Afterglow keeps track of it and says so). To undervolt you can pick a preset, click a point on your card's measured voltage/frequency curve, or edit the driver's curve point by point.

Runs your fans the way you want. Draw a fan curve, pick which temperature drives it (core, hot spot or memory junction), let the fans stop below a temperature, and stop them hunting up and down with hysteresis.

Tells you whether it's actually stable. A built-in burn test checks its answers bit for bit, so a single wrong bit is caught instead of waiting for a crash or for artifacts. There is a test for video memory, a stepper that walks your overclock up until it finds the edge, and a one-click certification that runs all four tests against a saved profile. If your PC does crash, the next launch explains what was happening in the seconds before.

Measures frame rates without injecting anything. Average FPS, 1% and 0.1% lows and a frametime graph for whatever game is running, read from Windows' own present events (the same method as NVIDIA FrameView and CapFrameX). No RivaTuner needed. Every capture is saved with the settings you were running, so you can compare before and after.

Remembers and automates. Save settings as named profiles, have a profile switch on when a game starts (and switch back when it closes), set a game's frame cap or vsync in the NVIDIA driver, or write rules like "if the memory gets to 94 °C for 30 seconds, run the fans at 90 %". Ctrl+Alt+R puts everything back to stock from anywhere.

Works from scripts and AI agents too. Everything is also in afterglow-cli, and afterglow-cli mcp lets an AI agent monitor, tune and stability-test the card through the Model Context Protocol, within the same limits as the app (docs/agent-integration.md).

The full list, with how each feature works and where it was tested, is in docs/features.md.

V/F Curve: the driver's stored curve (gold) with the measured one on top as it builds up	Fans: firmware, fixed or your own curve, driven by any temperature
Profiles: saved, tested, certified, and per-game rules	Settings: startup, logging, alerts, automation, overlay

_{All screenshots are real captures from an RTX 5090 on driver 617.42, made with tools/screenshots.ps1.}

Why another tuning tool?

• No kernel driver. The popular tools install one, and those drivers have a history of security holes: MSI Afterburner's RTCore64.sys has had several CVEs, one used by ransomware to switch off antivirus, and it is listed on loldrivers.io and has run into anti-cheat systems. Afterglow uses only the documented user-mode interfaces that come with the graphics driver: NVML and NVAPI from NVIDIA, IGCL and Level Zero from Intel.
• Open source under the MIT licence. You can read exactly what it does to your card.
• Honest. If your card or driver doesn't support something, Afterglow says so instead of showing a made-up number. Limits are listed below, and measurements come with their method.
• Light. Sitting in the tray it uses about 130 MiB of memory and about 0.3 % of one CPU core on the test machine, almost all of that being the driver answering the once-a-second sensor read (docs/performance.md).

Intel Arc (beta)

The same app also runs on Intel GPUs, through Intel's own documented interfaces. Every feature is checked against your exact device before it appears, so you only see what your card and driver actually support.

On the one Intel GPU it has been verified on (an Arc B390 in a handheld), you get live monitoring, the frequency clamp (Intel's driver can report it back, so every change is confirmed), the full stability lab, profiles with certification and FPS capture. That device has no temperature sensors, no fan control, no power-limit control and no clock offsets, and Afterglow says so instead of guessing. Discrete Arc cards will likely offer more. If you have one, please run afterglow-cli selftest and post the output in an issue: your driver will answer differently than the one it was tested on. The details are in docs/research/intel-driver-apis.md.

How it compares

	Afterglow	MSI Afterburner	NVIDIA App	ASUS GPU Tweak III
Open source	Yes (MIT)	No	No	No
Kernel driver	None	RTCore64.sys	None	Yes
Manual clock offsets	Yes, checked against the driver	Yes	No	Yes
Undervolting on RTX 50	Measured curve + click-to-undervolt	Curve editor	No	V/F tuner
Fan curve driven by memory temperature	Yes	No	No	No
Memory junction temperature on RTX 50	Yes	Plugin	No	Unknown
Throttle reasons in plain language	Yes	No	No	No
FPS and 1%/0.1% lows without RTSS	Yes	Needs RTSS	1% only	OSD
Per-game profiles that switch back	Yes	No	No	Profile Connect
Stress test that checks for errors	Yes	Separate app	No	Separate app
Automatic stability search	Yes, open method	OC Scanner	Auto-tune	OC Scanner
Reset after a driver crash	Yes	No	Manual	No
Command line	Full	Profile switching	No	No
Telemetry or account	None	None	Telemetry	Vendor services

Researched against current releases in 2026; sources are in docs/research/competitive-landscape.md. Corrections are welcome.

Getting started

1. Install. Download Afterglow-x.y.z-setup.exe from Releases and run it. Or take the portable zip, unzip it anywhere and run Afterglow.exe (keep the folder together). Windows 10 or 11, 64-bit, with NVIDIA driver 555 or newer (or a current Intel Arc driver). Nothing else to install.
2. Accept the admin prompt. Changing clocks, power and fans needs administrator rights, as it does for every tool like this. If you say no, Afterglow still runs and shows everything; it just can't change anything.
3. Try a gentle undervolt. On the Tuning page, pick Balanced in the undervolt wizard and press Apply. Your card should run nearly as fast on less power, which means cooler and quieter.
4. Check it. On the Stability page, run the burn test for a few minutes. If it reports an error, back off; if it passes, run the other two patterns too before you trust it.
5. Keep it. Save it as a profile, mark it stable, and choose it under Settings → Apply a profile at startup. Only profiles marked stable ever apply themselves, so an untested overclock can't load at boot.

Releases aren't code-signed yet, so Windows SmartScreen may warn the first time: choose More info → Run anyway. Each release lists SHA-256 checksums you can check the download against.

Good to know

• Made for NVIDIA RTX 20 series and newer, tested most on RTX 50 (an RTX 5090). Intel Arc support is in beta and verified on one device so far (see above).
• No hot-spot temperature on RTX 50. NVIDIA blocks it in every public interface; tools that show it read hardware registers through a kernel driver, which Afterglow doesn't have. Memory junction temperature does work and is shown.
• The per-point curve editor uses NVIDIA interfaces that aren't publicly documented (the same ones Afterburner's curve editor uses). It's verified on an RTX 5090 and only appears when your driver answers. Applying a core offset rewrites the whole curve, so set the offset first and shape the curve after.
• Per-game driver settings for games the driver doesn't know create a small driver profile for the game. Versions up to 1.2.0-beta.4 had a bug that left a profile named "A" behind instead; afterglow-cli drs --cleanup finds it and, with --apply from an admin terminal, removes it.
• The overlay can't draw over old-style exclusive fullscreen, because nothing is injected into the game. Borderless, windowed and modern "fullscreen optimized" games work.
• There's no temperature-limit slider on current RTX 50 drivers through public interfaces; use the power limit and the fan curve instead.
• More than one NVIDIA card is supported (a selector appears in the title bar), but it hasn't been tested on a real two-card system yet (#1).

Command line

afterglow-cli comes with the app. Changes need an admin terminal.

afterglow-cli selftest          what this GPU and driver support
afterglow-cli monitor           live sensors (--csv file to log them)
afterglow-cli caps | get        legal ranges / what is applied now
afterglow-cli set               --core-offset 150 --mem-offset 500 --power-limit 500
                                --lock-clock 2650 --fan 60 ...
afterglow-cli reset             back to driver defaults
afterglow-cli fps               frame rates of everything presenting
afterglow-cli stress            burn test (--pattern sustained|transitions|excursions)
afterglow-cli vram              video-memory test
afterglow-cli certify           all four stability tests against a saved profile
afterglow-cli drs               per-game driver settings (--exe game.exe --cap 120 --vsync off)
afterglow-cli drs --cleanup     find the "A" profile left by 1.2.0-beta.4 and earlier (--apply removes it)
afterglow-cli mcp               Model Context Protocol server for AI agents

Run afterglow-cli help for everything else.

Building from source

git clone https://github.com/minewefu/afterglow
cd afterglow
dotnet build        # needs the .NET 10 SDK
dotnet test
dotnet run --project src/Afterglow.App -- --demo

--demo runs the whole app on a pretend GPU, so you can work on the interface without an NVIDIA card. --data-dir <folder> keeps all settings, profiles and logs in that folder instead of %ProgramData%\Afterglow, so a test build never touches your installed copy. The tools folder has the scripts that make the screenshots above (screenshots.ps1), check the interface (ui-check.ps1) and measure performance (measure-perf.ps1). Design rules: docs/design.md.

Safety

Afterglow only writes values the driver itself says are legal for your card, and reads each one back wherever the driver allows it. Clock and power settings don't survive a reboot unless you choose a startup profile. If the driver crashes while you're tuned, Afterglow resets to stock; if the PC crashes, the next launch offers to. Overclocking is still overclocking: you own the risk, and an error in the stress test means back off.

Which driver interfaces are used, and how each was verified on real hardware: docs/research/driver-apis.md.

Credits

• Intel PresentMon (MIT) does the frame capture; the bundled binary, its licence and its pinned hash are in ThirdParty/PresentMon and THIRD_PARTY.md.
• LibreHardwareMonitor and NvAPIWrapper published the NVAPI knowledge the interop layer was built from (no code copied).
• Intel's published IGCL and Level Zero headers (MIT) for the Intel structure layouts (no code copied).
• CapFrameX and Gamers Nexus for the frame-metric definitions.

MIT licensed. Not affiliated with or endorsed by NVIDIA or Intel.