Gaming Performance

The Corsair Xeneon 27QHD240 OLED sports a 240 Hz refresh rate WOLED panel, which supports the adaptive synchronization technology on AMD, NVIDIA, and Intel graphics cards. The adaptive synchronization range is 40–240 Hz, so that's the framerate range your PC should be able to achieve at 2560x1440 resolution to experience buttery smooth, screen-tear-free gameplay. For modern mid-range gaming rigs, that's not too hard of a challenge.

Response Time and Overdrive

I tested the response time with the Open Source Response Time Tool (OSRTT), developed by Andrew McDonald of TechTeamGB. It's a nifty tool that, combined with the OSRTT Launcher app, measures panel response times and presents them through detailed graphs and easy-to-read heatmaps. You can find everything you might want to know about the OSRTT in its technical documentation and on the official website, where you can order your unit, too. The OSRTT gives us three interesting heat maps to observe.

Perceived Response Time tells us how much time the panel took to transition from one color to another. This measurement is expressed in milliseconds and includes overshoot. In other words, if the panel exceeded the target value, the perceived response time also includes the time it took for the transition to recover from overshoot and stabilize on the target value. I'm running my tests with recommended settings, so with a fixed RGB 5 tolerance level and with gamma-corrected RGB values.

RGB Overshoot tells us how much a specific transition missed the target value. For example, if the panel was transitioning from RGB 51 to RGB 204, and it initially landed on RGB 212, the overshoot RGB value is 8. Overshoot can be both positive and negative, and it commonly occurs at extreme overdrive settings when pixels are driven by high voltage. In practice, an overshoot manifests as an afterimage or a halo around a moving object. It can be easily spotted even when doing something as basic as scrolling through a webpage.

Visual Response Rating is the most abstract heatmap generated by the OSRTT Launcher; in essence, it's an ever-evolving scoring system. To quote OSRTT's technical documentation, it is a finite score rather than a direct measurement. The calculation is pretty simple; it's: "100 – (Initial Response Time + Perceived Response Time)." Since both metrics use the same tolerance level, if a display doesn't overshoot, both times will be identical. This essentially rewards displays that are fast with a small amount of overshoot over displays that aren't as fast even if they don't overshoot at all – while still overall preferring ultra-fast, accurate monitors.

Here's how the Corsair Xeneon 27QHD240 OLED fares in the pixel response time test.



This is pretty much as good of a result as you can hope for. With the average perceived pixel response time being as low as 0.71 ms, it's obvious that the Corsair Xeneon 27QHD240 OLED is an outstanding choice for blur-free gaming. Monitors like these push my measurement device to the limit so that's why we see these two red fields in the overshoot heatmap. There's no ghosting or overshoot to note at any given refresh rate; OLED panels are known for sustaining their pixel response performance regardless of the refresh rate. That comes as great news to anyone using adaptive synchronization technology, especially when playing a game where your PC struggles to maintain a stable framerate.

Input Lag

To measure the input lag of a monitor, I switched from using the LDAT V2 (Latency Display Analysis Tool), which I've covered extensively in my NVIDIA Reflex review, to the OSRTT Tool. The OSRTT Tool and the accompanying software include a DirectX code developed by Andrew McDonald of TechTeamGB, which allows the OSRTT Launcher to track the events and capture the frame time, making it possible to isolate the monitor latency from other factors that come into play when using the click-to-photon testing methodology, namely the USB polling rate and game render time. For a deeper insight, I suggest you watch an excellent overview video made by Andy himself.

While I used a consistent methodology in all my previous LDAT-based monitor reviews and kept everything the same, switching to the OSRTT-based approach isolates me from potential issues, such as game engine updates (I based my tests on Overwatch, which transformed into Overwatch 2), and allows me to move on to a different testing system at will. I have to admit it was becoming increasingly annoying having to keep my old Core i9-9900K/RTX 2080 Super test system around for nothing but monitor input lag testing. Thanks to Andy for his tireless work on the OSRTT Tool and the OSRTT Launcher software!

Here's how the Corsair Xeneon 27QHD240 OLED holds up in terms of input lag after doing 100 iterations of the input lag test.



The Corsair Xeneon 27QHD240 OLED shows an average input lag of around 6.4 milliseconds, which is a great score for a gaming monitor. Such low input lag can't be picked up even by the most hardcore gamers, including esports professionals.