Should you use NVIDIA Reflex?

Nvidia wants to help you click heads by lowering your system latency.

Image via Nvidia

Nearly every company with its hands in PC gaming hardware is rallying to combat one of the most significant issues in competitive gaming: latency. 

Some players may have never looked into their system latency. Others have watched countless videos to tune their settings to drop their system latency to the lowest possible value. Tuning your settings is an effective method of lowering system latency, but Nvidia is taking it a step further with the continued rollout of its Reflex technology. 

Reflex, Nvidia’s esports-focused low-latency platform, aims to be at the front of the push to eliminate system latency. While it may not be massively beneficial for every type of gamer, Nvidia’s Reflex technology is a convenient and developing answer to the complex issue of system latency in some cases. 

What is system latency? 

To set some groundwork for our experiment, we need to have a broad understanding of what causes end-to-end system latency, more commonly referred to as input lag. The “end-to-end” indicates that system latency is measured from the moment you click your mouse to the time that information is displayed on your monitor. System latency isn’t caused by one component alone, as the diagram below illustrates. Everything from your mouse to your CPU and GPU to your game of choice affects system latency. A few prominent players in system latency are the CPU, the render queue, and GPU. 

Image via Nvidia

The CPU, render queue, and GPU each play a pivotal role in determining your system latency because of how they interact with each other. In specific scenarios, you may become GPU or CPU bound. GPU-bound scenarios occur when your graphics card is maxed out and can’t keep pace with your CPU. This scenario causes a backup in the render queue between the CPU and GPU. The backup in the render queue then causes the CPU to slow its processes while the GPU plays catchup, resulting in higher latency.  

If you’re curious to see if you might be GPU or CPU bound, pull up your Task Manager by pressing Ctrl+Alt+Delete and click on Performance. Keep an eye on your GPU and CPU usage while in-game to determine whether you might be CPU or GPU bound. If your GPU’s utilization is disproportionately higher than your CPU, then you’re likely GPU bound. An example would be your GPU hitting above 95-percent utilization. Additional programs like HW Monitor, GeForce Experience Performance Hud, and MSI Afterburner provide more in-depth system information if you’re looking for something more precise. 

Why should you care about system latency? 

If you’ve ever been in the middle of a heated match and swore you hit the shot on an enemy or got peeked by a player who couldn’t have possibly seen you coming, system latency may have played a part. 

Milliseconds matter in competitive gaming, and those tiny pockets of delay can make the difference between clutching up or getting rolled. Granted, there are some factors that Reflex can’t control, like network latency, but it can help mitigate the issue by reducing latency in other ways.

What does NVIDIA Reflex do? 

Reflex is an esports-focused technology that measures system latency and can help reduce it in some instances. There are a couple of different components to the Reflex ecosystem, but we’ll be zeroing in on the part of Reflex that actively reduces latency. 

Reflex is, in part, a software development kit (SDK) developers implement into their games to give players the option to reduce system latency through the in-game menu. When integrated into a game by its developers, Reflex reduces system latency in GPU-heavy situations when the setting is active. 

Nvidia’s Reflex technology drops latency by preventing you from becoming GPU bound. Reflex achieves this by keeping the CPU and GPU in sync with one another. Keeping the GPU and CPU at the same pace prevents the render queue from backing up and provides a steady stream of frames for your GPU to render and display. Likewise, enabling Reflex with Boost can lower latency in extreme CPU-bound scenarios. An example of this scenario is pairing a much older CPU with a new GPU or if GPU utilization drops below 40 percent.

Reflex is available in seven of the top 10 competitive esports titles, including Fortnite, Rainbow Six Siege, CS:GO, Overwatch, VALORANT, Call of Duty: Warzone, and Call of Duty: Modern Warfare, with more to come. Users can typically toggle the Reflex setting in the display settings of compatible titles but will need a 900 series GPU or better to take advantage of Reflex.

Testing equipment

Our reviewer tested Reflex with three different Nvidia graphics cards across three esports titles using Nvidia’s Latency and Display Analysis Tool (LDAT). This tool uses a luminescence sensor to monitor the latency between a mouse click and the muzzle flash displaying on the screen. 

To test Reflex, our reviewer attached LDAT to the monitor with the luminescence sensor facing the display and positioned it over the Latency Flash Indicator. The sensor is connected to a compatible mouse that plugs into the PC as it normally would. From there, our reviewer set a sample rate of 20 and enabled LDAT’s Auto Fire feature. Auto Fire tricks the mouse into thinking the left mouse button has been clicked, causing the in-game weapon to fire. 

Using LDAT’s Auto Fire feature, our reviewer gathered 20 samples using a 360Hz Alienware AW2521H monitor with an Nvidia GTX 1080, RTX 3070, and RTX 3080 in Fortnite, Overwatch, and Rainbow Six Siege. Our reviewer tested each title and GPU with Reflex Off, On, and On with Boost enabled and graphics set to the highest preset at 1080p.

For users planning to experiment at home with Nvidia’s Reflex Latency Analyzer, note that results will vary based on your rig’s hardware. Our reviewer was also heavily CPU-bound in some instances with the 3070 and 3080.

Fortnite results

Starting with Fortnite, we can see that Reflex is accomplishing what it sets out to achieve. While results vary from GPU to GPU, the trends stay fairly consistent across the board. Fortnite is also the only game tested featuring an updated Boost optimization that helps more in certain CPU-bound scenarios. Because of this optimization, results are not indicative of how every game performs with Boost enabled. 

The more commonly used 1080 sees the bulk of the benefits with a 9.55-millisecond decrease in system latency with Reflex On. That figure drops an extra 3.11 milliseconds with Boost enabled for a total reduction of 12.66 milliseconds. 

Meanwhile, the 3070 only saw a 1.32-millisecond decrease in latency with Reflex On and a 4.44-millisecond decrease with Boost enabled. Because the 3070 outpaces the 1080 by leaps and bounds, its base latency is already much lower. Still, Reflex achieves what it intends to do with the 3070. 

Nvidia’s 3080 undercuts both the 3070 and 1080, as expected. Enabling Reflex nabbed our reviewer a meager .33-millisecond latency drop. Using Boost shaved a total of 1.89 milliseconds off the total latency, which doesn’t prove there is a difference in terms of real-world performance.

Overwatch results 

Overwatch is where Reflex shined brightest during our reviewer’s tests. That being said, enabling Boost had little effect across the board. The lack of variation between Reflex On with Boost enabled and Reflex On alone makes sense given that Boost only kicks in once your GPU utilization drops below 40 percent, which was not the case in our reviewer’s experience. 

Once again, the 1080 benefits the most from Reflex, dropping latency by 13.66 milliseconds. Enabling Boost docked our reviewer .77 milliseconds, but this looks more like a run-to-run variation given the tight gap and probability that GPU usage didn’t drop below 40 percent. 

Reflex dropped latency by 2.15 milliseconds using the 3070. Results here were tight, with Boost narrowly squeezing under Reflex On by a mere .11 milliseconds. Again, this is another tight gap that may vary on a run-by-run basis considering the results of the 1080 and 3080. 

Starting out with just 11.97 milliseconds of latency already puts the 3080 near the sub-10-millisecond sweet spot. Reflex dropped the latency by another 1.47 milliseconds. Using Boost reduced latency by 1.12 milliseconds, which comes in slightly over Reflex without Boost enabled. These results are likely run-to-run variations that could fluctuate due to flipping back and forth between being GPU and CPU bound. 

Rainbow Six Siege results 

Reducing latency in a game like Rainbow Six Siege is a tall order. Because Siege is already optimized to operate at lower latency than the other titles tested, reducing latency further is a challenge. Nevertheless, results look consistent with what we see in Overwatch, including probable shifts between being GPU and CPU bound. If this weren’t the case, our reviewer wouldn’t have seen any noticeable difference between having Reflex On or Off. 

Interpreting Siege’s latency data is slightly different due to operating below 15 milliseconds. As such, the differences between Reflex settings look much larger than in reality. But as expected, the 1080 seems to benefit the most from Reflex and nabs a 2.04-millisecond dip in latency. The 3080 is of particular interest. Rainbow Six Siege is the only title that clocked the 3080 as being slightly slower than the 3070 by 1.06 milliseconds, which is somewhat of an oddity given its raw power.

Should you use Nvidia Reflex?

The short answer is yes. Players can only stand to gain from using Reflex since it never dings your system latency and can only reduce it. Even in situations when Boost ran a bit higher than Reflex On, it never harmed system latency. 

Regarding real-world differences, users with older GPUs will notice more of a change than those with newer Nvidia cards. Being GPU bound while running a 30 series at 1080p with settings maxed out is unlikely. Unless you’re playing with ray tracing enabled or in 4K, Reflex won’t be able to help much. Even then, most competitive players don’t use the highest graphics settings strictly because of that added latency. Like 8,000Hz polling rate gaming mice, it’s also probable that few players will benefit significantly from the slight performance bumps granted by Reflex. But an important differentiation is Reflex doesn’t cause your CPU usage to spike like an 8,000Hz mouse. 

Having Reflex enabled can also help in situations when you become GPU bound for brief periods. This fluctuation seemed to be the case with our reviewer’s Overwatch and Rainbow Six Siege results. Realistically, Reflex shouldn’t have made a dent in latency while testing the 3080, but it did anyway. This result reflects being GPU bound for a few frames here and there.

Despite not being useful in every situation, Reflex presents some exciting prospects for latency reduction and competitive gaming.