Nvidia Reflex and AMD Anti-Lag: what they do and when to turn them on
Your game has a Reflex or Anti-Lag setting and you're not sure whether to turn it on. Almost always yes, and here's why it helps more in some games than others.
Where the lag comes from
From click to picture on a PC, the time is roughly: the mouse or controller report, the game reading input and working out the frame on the processor (CPU), the frame waiting in a queue, the graphics card (GPU) drawing it, then the screen. The queue is the part that grows when the GPU is busy. With two or three frames waiting at 60 fps, that's 30 to 50 ms of delay that does nothing useful. The interactive Wirebook lesson on how a controller talks to a console explains why controllers only ever send the newest snapshot; Reflex applies the same idea to frames.
The options compared
| Setting | Where | What it does | Notes |
|---|---|---|---|
| Nvidia Reflex: On | In supported games | Paces the CPU so frames don't queue for the GPU; input is read as late as possible | GeForce GTX 900 series and newer. Biggest effect when GPU-bound |
| Reflex: On + Boost | In supported games | The same, plus keeps GPU clocks high | Small extra help when CPU-bound; uses more power |
| Nvidia Low Latency Mode (On / Ultra) | Nvidia Control Panel | Limits how many frames the CPU may prepare ahead; Ultra submits just in time | For games without Reflex. Only applies to DirectX 9 and 11 games, and a game with Reflex overrides it |
| AMD Anti-Lag 2 | In supported games | In-game pacing, similar to Reflex | Radeon cards; fewer games than Reflex so far |
| AMD Anti-Lag | Adrenalin driver | Driver-level pacing for any game | Smaller effect than the in-game versions |
One caution: AMD's earlier Anti-Lag+ worked by changing game code from the driver, and in 2023 some players using it in online games were flagged by anti-cheat. AMD withdrew it; the in-game Anti-Lag 2 doesn't have that problem.
When it helps a lot, and when it doesn't
- Big win: high settings or resolution with the GPU at 95 to 100%, uncapped frame rate. This is the case Reflex was made for.
- Small win: the GPU has headroom because the frame rate is capped (by V-Sync, a limiter or the screen) or settings are low. The queue was already short.
- CPU-bound games (big strategy games, busy online cities): little change, though On + Boost can help slightly.
- Frame generation (DLSS Frame Generation, AMD's frame generation) adds lag because it holds a real frame back to make the in-between one. Reflex or Anti-Lag 2 is switched on with it to win much of that back, so leave it on.
Does it lower FPS?
Usually by nothing to a few percent, because the GPU is kept just as busy, only without a backlog. Reflex can also cap the frame rate slightly below the refresh rate when G-Sync and V-Sync are on, which is intended: it keeps you inside the VRR range.
The order that usually matters most
- The screen: game mode on a TV, a faster refresh rate on a monitor. See 60 vs 120 vs 144 Hz.
- Frame rate, and VRR instead of plain V-Sync.
- Reflex or Anti-Lag 2 on (pick "Low-latency mode on" as the game setting in the input lag calculator to see the effect).
- Then the cable and polling rate.
Related
Frame pacing and stutter · VRR, G-Sync and FreeSync explained · 60 vs 120 vs 144 Hz: can you tell? · TV game mode: what it does · Controller lag: wired vs wireless vs Bluetooth
Questions
Should I turn on Nvidia Reflex?
Yes. It reduces input lag, most when your graphics card is near 100%, and costs little or no frame rate.
Reflex On or On + Boost?
On is right for most people. On + Boost keeps the graphics card's clocks high, which can help slightly when the processor is the bottleneck, but uses more power and heat.
Does Nvidia Reflex reduce FPS?
Usually not noticeably. It removes the queue of waiting frames rather than slowing the graphics card. With G-Sync and V-Sync on it may cap fps a little below your refresh rate on purpose.
What is the difference between Reflex and Low Latency Mode?
Reflex is built into the game and paces frames precisely. Low Latency Mode is a driver setting for games without Reflex, works only in DirectX 9 and 11 games and has a smaller effect.
Is AMD Anti-Lag safe to use in online games?
The in-game Anti-Lag 2 and the regular driver Anti-Lag are fine. The earlier Anti-Lag+ triggered anti-cheat in some games in 2023 and was withdrawn.
Why does frame generation need Reflex?
Frame generation holds back a real frame to create the one in between, which adds delay. Reflex or Anti-Lag 2 removes queue delay elsewhere to make up much of it.
Published 路 updated .