Hardware-Accelerated GPU Scheduling (HAGS): what it changes and whether to enable it
SHORT ANSWER
HAGS writes HwSchMode to SYSTEM\CurrentControlSet\Control\GraphicsDrivers — 2 enables it, 1 disables it — and moves parts of frame scheduling from the driver onto the GPU. It is required for DLSS Frame Generation. Otherwise it is one of very few settings where you genuinely have to test: it improves frame-time consistency on some CPU and driver combinations and introduces stutter on others, with no way to predict which from specifications.
Exactly what it changes
Read straight from the application source. If a tool will not show you this, it is asking for trust it has not earned.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers
HwSchMode = 2 (enabled) / 1 (disabled)
Tells the graphics stack whether the GPU may manage its own frame queue.
What it does
Normally the graphics driver batches and schedules the work sent to your GPU. HAGS hands a portion of that scheduling to a dedicated processor on the GPU itself, shortening the path between your game submitting a frame and the GPU starting it.
The change takes effect after a reboot, which is why toggling it and immediately benchmarking shows nothing.
When it helps
- It is a hard requirement for DLSS Frame Generation. If you use frame generation, HAGS must be on.
- On recent CPU and driver combinations it often flattens frame times slightly, which shows up in 1% lows rather than average FPS.
- It can reduce CPU overhead in games that submit a very large number of draw calls.
When it hurts
- On some older CPUs and specific driver revisions it introduces periodic stutter. This is well documented and not rare.
- A handful of capture and overlay tools have historically misbehaved with it enabled.
- It is not a free win. Anyone telling you to always enable or always disable it has not tested it across enough machines.
How to undo it
Set HwSchMode back to 1 and reboot, or use Settings > System > Display > Graphics > Change default graphics settings and turn the toggle off. Frozen Tweaks records the previous value and restores exactly that.
Verdict
Test it. Benchmark the same scene twice, once in each state, and keep whichever gives better 1% lows. If you use DLSS Frame Generation the decision is made for you.
Related guides
Everything else we change is listed too
All 127 optimizations are published in full, with what each one does and which are free. You can apply any of them by hand using pages like this one — the tool exists to do it in one click and put it back after every Windows update.