NVIDIA Reflex reduces the delay between your actions and reactions on the game field.
When measuring the performance of graphics cards, we primarily focus on frame rate. This is a fairly visual indicator, and more experienced players can tell at a glance whether a game is running at 20, 50, or 120 frames per second.
But for fast-paced action games, it’s not just how smooth the game is, it’s how quickly it can respond to your keystrokes and movements or mouse clicks. Before the result of your action is displayed on the monitor, many things have to happen, and each of them takes the computer some time. A few milliseconds may not seem like a big deal, but when the game lags by those “few” milliseconds in every place it can lag, it’s tens of milliseconds.
It’s not just milliseconds
If you add up all these small delays, the result can already reach the level of tenths of a second. And you don’t even have to be a professional gamer to feel that the game is a little lazy and you have a hard time getting through the door when sprinting.
A quality gaming mouse with a high sampling rate will help a lot at the beginning of the chain. That being said, calculating the image and rendering it on the monitor is usually where the most lag occurs. Frame rate is a measure of how long it takes to render the image. It’s easy to calculate that at 30 fps it takes about 33 ms to render, at 60 fps it takes 16.7 ms, at 120 fps it takes just over 8 ms, and at 240 fps you can get just over 4 ms. This is why action gamers strive for the highest frame rate possible – at 240 fps it’s not that the game is smoother than at 90 fps, but rather that at 90 fps the rendering of a single frame is delayed by 11 ms, and per second in this case it’s only 4 ms. These are still small numbers, but it usually takes more than one frame to render the mouse’s response to the screen.
For a monitor, it depends on how quickly it can redraw the display and at what point in the redraw process it receives the new image. With Vsync, if a frame arrives just before the image is due to be redrawed, the monitor can begin rendering it immediately. If it arrives after the image has begun to be redrawed, it will wait in a queue for the entire time the image is being redrawed. On a 60Hz panel, the redraw takes 16.7ms, the same as when rendering at 60fps. Even when the image is ready, it may be delayed another 17ms just because the monitor is redrawing.
In classic LCDs, the crystals take a few more milliseconds to flip to the right side. Although various tricks, such as overdrive, will help them with this. Worse, the liquid crystals usually don’t orient themselves perfectly in one pass, but ghosts remain from the previous frame. Judging by the 1ms paper response of high-end LCDs, it’s more like two or three screen redraws before the subpixels permanently change their hue and become beautifully colored.
In this regard, monitors with OLED displays, which simply turn off or turn on individual pixels, have a huge advantage. The latest news on the market is a series of displays with new 32-inch QD OLED panels from Samsung. LCD displays are incomparable in terms of gaming parameters, and even compared to older OLED panels, they no longer make any compromises in terms of resolution or refresh rate. They offer a solid 32-inch diagonal with 4K resolution and a high refresh rate of 240 Hz.
one of them is AORUS FO32U2P from a proposal from Gigabyte that we were able to borrow to measure the impact of Reflex on response in games.
And I was extremely happy about this, because the key to measuring the response is the high-class response of the monitor itself, the extreme pixel redrawing speed compared to LCD and the high refresh rate of 240 Hz, which means that thanks to the redrawing of the monitor, the measurement error caused by the redrawing of the monitor itself is a maximum of four milliseconds (while with G-Sync it can be shorter due to the possibility of waiting for the frame to be rendered).
To prevent your computer from slowing down unnecessarily
If a game is to respond as quickly as possible to the player’s movements, it is desirable to have as little lag as possible between the mouse and the monitor, and this is exactly what NVIDIA aimed for when creating the Reflex interface.
NVIDIA Reflex SDK is a set of APIs for game developers that not only reduces latency, i.e. speeds up the system’s response to input from controllers, but also measures the length of the response. It works on all GeForce models from the GTX 900 series and above.
The entire ecosystem and response issues are discussed on several pages and subpages of the site. NVIDIA, something else in Czech. With Reflex, the game engine can be fine-tuned to ensure that rendering occurs just in time (in the case of delivery, this is called just in time). With an API that reduces the graphics rendering queue directly in the game, the response can be reduced more significantly than was possible, for example, with optimization via drivers. Through them, for example, it was not possible to control when the game would read the mouse movement before rendering the image and when the processor would start working with the scene. However, with Reflex, this can be influenced and thus the response can be reduced by up to a third.
Since Reflex launched, more than 110 supported titles and others are growing rapidly, among other things, because they are an integral part of DLSS frame generation. In games that support frame generation, this is implemented precisely to reduce responsiveness, which would otherwise be stretched due to the delay of the last rendered frame due to the display of the generated intermediate frame.
Typically, games have two modes to reduce lag:
- Reflex on or off: Optimizes rendering, eliminates GPU queues, and reduces CPU requirements in GPU-limited scenarios, resulting in lower latency and faster gaming response.
- Reflex on + gain: Enables classic Reflex optimizations, but also keeps the GPU clock high even when it’s idle due to CPU bottlenecks, further reducing latency at the cost of higher power consumption.
In most scenarios, the differences between the two modes are insignificant. Let’s see how Reflex helps reduce responsiveness in Gray Zone: Warfare and Overwatch 2 on a mid-range GeForce RTX 4070 Super.
In particular, it is well equipped. Gigabyte GeForce RTX 4070 Super Aero OC 12G in an attractive design with a bright white three-slot cooler with three counter-rotating fans, not lacking illumination with addressable RGB LEDs, dual BIOS or a metal backplate protecting the rear of the card.
Let’s take a couple of games as an example – the popular Overwatch 2 and the new Gray Zone: Warfare, which you can play in early access.
I measured the game’s response primarily when it’s displayed directly on the monitor using OSLTT, an open-source latency testing tool. It simulates mouse action and uses a sensor to measure the change in screen brightness after the game reacts to the input stimulus. This way, it measures quite accurately how long it takes for the image on the monitor to respond to the mouse movement.
Overwatch 2 has very light graphics. I tested on the Watchpoint: Gibraltar map in Skirmish mode with boots and the global Ultra setting with offsampling (render scale 100%) and for each resolution I added reflex and DLSS at the recommended quality (Quality for 1080p, Balanced for 1440p and Performance for 4K).
Obviously, if your game runs at 1080p on an RTX 4070 Super at 370 fps and renders a frame in 3 ms, there’s not much to improve on with Reflex. However, if you want to enjoy high detail and 4K visuals on such a card, the advantage of Reflex is already quite significant.
To get a better idea of how a shorter response time will work in practice in this case, I will also offer you slow motion footage, where you can see the delay between the mouse movement and the reaction on the monitor. . Even better to determine whether you slow down the video in the playback settings, or you can simply pause it and step through the frames using the dash and dot keys on the keyboard (near the M and N keys, so it is easier to remember by the shortcuts “<“ a „>“from the English keyboard).
Grey Zone: Warfare has great graphics thanks to the Unreal Engine, but it is very demanding and does not allow for much detail reduction as the entire game is designed to highlight the realistic game environment, including dense forests and complex topography, providing strategic advantages and better coverage for players.
At higher resolutions, where the frame rate is not limited by the processor’s performance, Reflex helps reduce response time by tens of milliseconds. I measured the difference in two ways this time – you can try the second one yourself using the FrameView application, which allows you to display the current computer response directly on the monitor, measured by the Reflex libraries implemented in games. In the OSD, this is the PCL value in milliseconds.
In the graphs you will find three measurements for each resolution. For higher performance and better image quality than the built-in TSR upscaling, I used DLSS in quality mode. Each of the settings is tested without NVIDIA Reflex enabled, with Reflex enabled, and finally with Reflex enabled and DLSS image generation. This helps, especially at low resolutions where graphics are already limited by the processor, to significantly increase frame rates, but slightly increases response times. This is exactly the lag that Reflex is supposed to compensate for, and the results show that the game is better with responsiveness and image generation than without Reflex.
And again a video where you have a slow motion recording of the game reacting to the mouse in 4K resolution.
You can see from the graph that the values measured by OSLTT replicate the data from NVIDIA’s FrameView software quite closely, so if you own a GeForce card and haven’t yet researched whether Reflex will help you and if so, you might want to start right away.
Source : Zing
