Gaming Performance

The KTC H27T22 sports a 165 Hz refresh rate Fast IPS panel, which supports the adaptive synchronization technology from both AMD and NVIDIA graphics cards. The adaptive synchronization range is 48–165 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. The monitor is AMD FreeSync Premium certified, which means it supports the Low Framerate Compensation (LFC) technology. If the game runs at fewer frames per second than the bottom limit of the FreeSync operating range (48 FPS in this case), the LFC technology displays frames multiple times to stay above the lower limit of FreeSync and maintain the complete fluidity of the action. Of course, this "multiplication of frames" is entirely invisible to the human eye. Thanks to this approach, the bottom limit of the required number of frames per second becomes irrelevant and should not be considered. Of course, for the best possible gaming experience, a high framerate remains something you should strive for.

Response Time and Overdrive

The response time of the KTC H27T22 is specified as 1 ms GtG. The panel uses overdrive technology to make the pixel transitions faster, and you will find the option in the Gaming Setup > Overdrive menu in the OSD. Overdrive has four settings: Off, Low, Middle, and High.

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 own unit, too. The OSRTT gives us three interesting heatmaps 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 KTC H27T22 fares in the pixel response time test for all four overdrive settings. We're looking for a setting that has a low measured average perceived time value and as little overshoot as possible.






As you can see by examining the numerical data and accompanying heatmaps, the best overdrive setting is Low. It has a lower perceived pixel transition time value than when the overdrive is set to Off, and only a minor amount of overshoot, which I didn't find noticeable while gaming. The Middle setting doesn't improve perceived response time at all and introduces a substantial amount of overshoot. The High setting moves even further in the same direction, making it an even worse choice. All in all, set the Overdrive to Low, and enjoy!

Moving Picture Response Time (MPRT)

In the OSD's Gaming Setup menu, you'll find the MPRT toggle. If you turn it on, the backlight will start strobing to achieve a faster pixel response time at the expense of picture brightness. You're also losing the ability to use adaptive synchronization; turning MPRT on instantly deactivates FreeSync/G-SYNC. MPRT can be used with the refresh rate set to 165 Hz.

The MPRT response time is not to be confused with GtG response time, as the commonly used GtG value tells us how much time it takes for a pixel to change between two colors. At the same time, MPRT, also known as display persistence, represents how long a pixel is continuously visible. It's important to know that MPRT isn't a blur reduction technology but a measurement that can be lowered by backlight strobing.

Activating MPRT on the KTC H27T22 lowers the panel's maximum brightness down to 136 cd/m², and there's nothing you can do to increase it. As soon as you touch the brightness control, MPRT deactivates. That brightness is acceptable for nighttime gaming; otherwise, you'll want a brighter picture. There's no significant strobe crosstalk or any other issues which are regularly present when MPRT is used, and moving images are, in fact, even sharper, but the aforementioned low brightness, combined with the inability to use adaptive synchronization, as well as the fact that MPRT turns off and has to be reactivated every time you reset your PC, prevents me from recommending using this feature of the KTC H27T22. Moving images are very sharp with regular overdrive, so this isn't something worth losing sleep over.

Input Lag

To measure the input lag of a monitor, I recently switched from using the LDAT V2 (Latency Display Analysis Tool), which I've covered extensively in my NVIDIA Reflex review, to the OSRTT Tool. In a recent update, the OSRTT Tool and the accompanying software were upgraded with 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 recently 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 KTC H27T22 holds up in terms of input lag after doing 100 iterations of the input lag test.



The KTC H27T22 shows an average input lag of less than 4 milliseconds, making it a viable choice even for hardcore gaming.