A game’s performance doesn’t just come down to its framerate and graphics settings. Latency is also important, as this affects how snappy and responsive the game feels to play.
NVIDIA’s Reflex technology is one solution to the problem of latency while gaming. It attempts to reduce the delay between your mouse and keyboard inputs, and the resulting in-game action being displayed on screen.
In supported games on supported graphics cards, NVIDIA Reflex should improve your gaming experience by reducing such delay. This can be especially important for competitive eSports titles which require fast reaction times.
There is, however, debate about whether the reduction in latency that it provides is noticeable on many setups.
What is Latency in Gaming?
Latency refers to the amount of time it takes for data to transfer from its source to its destination.
Latency can occur over your internet connection if packets of data are taking a long time to be sent and received over your network and the internet. But it can also occur on your PC system itself, even in single player games.
When you move your mouse or press a key on the keyboard, your computer must take that input data and process it, then process and change the game state accordingly, and render this new game state to the screen.
The longer this takes, the more delay there is between your input, and this being visibly registered in-game. This is why system latency is often called ‘input lag’.
High system latency can be caused by any step in this chain – from your peripherals, the transfer of input data to your graphics card, your graphics card rendering new frames, or your monitor displaying these frames.
What is NVIDIA Reflex?
NVIDIA Reflex is a technology that attempts to reduce system latency in supported games on supported GPUs. You can turn it on or off in the settings menus of supported games.
To reduce system latency, it targets the rendering part of the pipeline. GPUs are told what to render by the CPU, and they often store these instructions in a ‘render queue’. NVIDIA Reflex eliminates the render queue, allowing frames to be rendered as soon as they’re instructed to by the CPU.
By eliminating the render queue and allowing the CPU and GPU to work in close to lockstep, there’s less delay between your input and that input being represented on your screen in-game.
NVIDIA Reflex Supported Games
NVIDIA’s Reflex technology is implemented via its Reflex software development kit (SDK). This means that, for a game to have Reflex tech, its developers must add support for it using the Reflex SDK.
You can find a list of all games that currently support NVIDIA Reflex on NVIDIA’s website.
Some notable games that currently support NVIDIA Reflex are:
- Apex Legends
- Call of Duty: Warzone
- Destiny 2
- Escape from Tarkov
- Rainbow Six Siege
NVIDIA Reflex Supported Cards
Any NVIDIA graphics card of 900-series or higher should be able to use NVIDIA Reflex in supported games. This means that the following GPU generations should support NVIDIA Reflex technology:
- NVIDIA GeForce GTX 900-series (‘Maxwell’) cards
- NVIDIA GeForce GTX 1000-series (‘Pascal’) cards
- NVIDIA GeForce GTX 1600-series (‘Turing’) cards
- NVIDIA GeForce GTX 2000-series (‘Turing’) cards
- NVIDIA GeForce GTX 3000-series (‘Ampere’) cards
All these generations should allow you to enable Reflex in supported games, but newer generations on the list might achieve lower latency with less of a framerate impact.
How to Enable NVIDIA Reflex
NVIDIA Reflex can be enabled or disabled in the settings menus of supported games. You should ensure you have the latest NVIDIA drivers and then navigate the in-game settings to enable it.
The Reflex option is usually located in the graphics menu. For example, in Overwatch’s settings you navigate to the ‘Video’ menu, then select the dropdown next to ‘NVIDIA Reflex’, where you can choose between ‘Disabled’, ‘Enabled’, or ‘Enabled + Boost’.
What is NVIDIA Reflex Boost?
As well as being able to enable or disable NVIDIA Reflex, some Reflex compatible games also give you the option to enable Reflex with ‘Boost’.
NVIDIA says, “Boost Mode increases GPU clock speeds in CPU-bound scenarios, allowing the GPU to submit frames to the display faster, thereby improving Reflex’s effectiveness.” So, enabling Reflex + Boost should both eliminate the GPU’s render queue and boost its clock speed to further lower latency.
How much this improves your latency and affects your performance depends on your hardware and the game in question, though.
Does NVIDIA Reflex Affect FPS?
Enabling NVIDIA Reflex shouldn’t affect your FPS much. Enabling the feature should barely lower your framerate but potentially significantly lower your latency. NVIDIA claims, for example, that enabling Reflex in Overwatch dropped system latency from 56ms to 28ms with a GTX 1660 Super at 60Hz in their testing.
I tested Reflex in Overwatch with my NVIDIA GeForce GTX 1070 graphics card, and got the following average framerates over the same 30-second test run:
|NVIDIA Reflex disabled||220.0 fps|
|NVIDIA Reflex enabled||219.7 fps|
|NVIDIA Reflex + Boost enabled||209.2 fps|
While the performance difference between ‘Reflex enabled’ and ‘Reflex disabled’ was negligible, enabling Boost actually lowered my performance.
NVIDIA’s Reflex Boost option should increase performance in theory, but it doesn’t work the same on all systems and in all games. You should compare framerates on your own system to see whether enabling Boost is worth it.
In my Overwatch testing, I didn’t notice any decrease in latency when toggling from Reflex disabled to Reflex enabled, but my system latency is already low.
If your GPU is powerful enough to keep up with all the rendering instructions fed to it by the CPU and process them right away, then there likely won’t be much of a rendering queue for it to work through and it should work through any rendering tasks very quickly. In such cases, enabling NVIDIA Reflex likely won’t reduce system latency very much.
But if you’re bottlenecked by your GPU then you should see latency improvements by enabling NVIDIA Reflex, because in such cases the GPU render queue that Reflex eliminates will have a bigger latency impact.
What is NVIDIA Reflex Latency Analyzer?
While big changes in system latency can be noticeable, often it’s hard to know whether latency changes are real or just the result of a placebo effect. Thankfully, NVIDIA has given us the Reflex Latency Analyzer.
NVIDIA’s Reflex Latency Analyzer is a tool that’s supported by some G-Sync monitors, and NVIDIA says it can be used for “easily and quickly measuring system latency”. Proprietary NVIDIA hardware is installed in such monitors to allow for system latency analysis.
To use the Latency Analyzer, you must connect your monitor to your PC via USB and then connect your mouse to your monitor, which it uses as a middle-man pass-through. Then enable the Analyzer via the monitor’s menus, adjust the analysis window to cover an area of the screen where an action will happen upon an in-game mouse click (such as over your crosshair), and click.
Your display should tell you what your system delay is in milliseconds (ms). You can compare the results of this test when Reflex is enabled and when it’s disabled to see to what extent enabling Reflex lowers your system latency.
Should you turn NVIDIA Reflex Low Latency On or Off?
The best way to decide whether to turn NVIDIA Reflex on or off is to test it yourself in-game. Simply toggle Reflex on in your game’s graphics or video settings menu. If your framerate barely drops and you notice a decrease in input lag, then leave it on.
In fact, in most cases it’s best to enable Reflex even if you don’t notice a latency improvement, because its performance impact is usually negligible, meaning it usually has no downside.
If your graphics card is bottlenecking your setup, then enabling Reflex will likely have a bigger, better impact by eliminating the render queue from the pipeline and drastically decreasing system latency. But if your graphics card is handling its rendering with ease, then you’ll likely see less of a latency reduction from enabling it.
Whether to enable NVIDIA Reflex Boost or not depends on your system and the game you’re playing. If you notice a significant drop in FPS when it’s enabled, then it’s probably better to stick with Reflex enabled but Boost disabled.