Gaming Performance

The Cooler Master GM34-CWQ2 sports a 180 Hz refresh rate VA panel, which supports the adaptive synchronization technology from both AMD and NVIDIA graphics cards. This is a clear improvement over the predecessor, which was equipped with a 144 Hz panel.

The adaptive synchronization range is 48–180 Hz, so that's the framerate range your PC should be able to achieve at 3440 x 1440 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 full fluidity of the action. Of course, this "multiplication of frames" is completely invisible to the human eye. Thanks to this approach, the bottom limit of the required number of frames per second become irrelevant and should not be thought about. Of course, for the best possible gaming experience, a high framerate remains something you should strive for.

Regarding the specified 180 Hz refresh rate, I find it interesting that the official specifications of the monitor state that the panel actually refreshes at 165 Hz, and 180 Hz is achieved by overclocking. I'm not entirely sure what's meant by that, because 180 Hz refresh rate is supported natively, without you having to do anything in an OSD menu or anywhere else. What's more, the OSD offers no refresh rate management options at all. The panel is factory-adjusted to 180 Hz, and it shows no signs of having any issues operating at that refresh rate. The difference compared to 144-hertz monitors is not at all drastic, but it can be felt even in everyday tasks such as browsing the web.

Response Time and Overdrive

The response time of the Cooler Master GM34-CWQ2 is specified as 2 ms GtG and 0.5 ms MPRT. The MPRT mode can be activated in the OSD, where it's called Motion Clearness.

The panel uses overdrive technology to make the pixel transitions faster, and you will find the option under Gaming > OverDrive in the OSD. Overdrive has a total of six settings: Off, Normal, Advanced, Ultrafast, Dynamic, and User. In Dynamic mode, the overdrive technology actively switches between the Normal, Advanced, and Ultrafast modes, in relation to the current framerate. The User option lets you manually set the overdrive level on a 0-100 scale.

I tested the response time with the Open Source Response Time Tool Pro (OSRTT Pro), 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 Launcher 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 Cooler Master GM34-CWQ2 fares in the pixel response time test.









After examining the results, including two manually adjusted overdrive settings (50 and 75), the Advanced option looks like the best choice for high refresh rate gaming. It offers an average perceived response time of 6.79 milliseconds, and overshoot occurs only in traces and is not noticeable in practice. Depending on the framerate/refresh rate you're hitting in the games you're mostly playing, you might want to try the Normal option, too. If you want to control the overdrive manually, it's best to experiment with it in the 40-50 range.

Moving Picture Response Time (MPRT)

In the OSD is the MPRT toggle, hidden under the Motion Clearness name. If you turn it on, the backlight will start strobing to achieve a "0.5 millisecond-like" response time at the expense of picture brightness and other strobing-related issues, such as flickering and strobe crosstalk. The Motion Clearness technology can be used together with adaptive synchronization and with refresh rates of up to 180 Hz, which wasn't the case with older or lesser MPRT implementations.

The "0.5 ms MPRT" response time is not to be confused with 0.5 ms GtG response time, as the commonly used GtG value tells us how much time it takes for a pixel to change between two colors, while 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. Here's a comparison of moving object sharpness with Motion Clearness set to Low, Medium, and High.

Activating Motion Clearness lowers the maximum brightness of the panel and locks you from changing it in any direction. Namely, when set to Low, the panel brightness drops to 175 cd/m². Setting it to Medium lowers the brightness to a mere 105 cd/m², and setting it to High results in only 51 cd/m² of actual screen brightness. In other words, with Motion Clearness set to Medium or High, the monitor is more or less unusable. I wouldn't bother using it at Low either to be honest, because 183 cd/m² isn't particularly bright either, and there's still some apparent strobe crosstalk present.

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 Pro Tool. The OSRTT Pro 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 Cooler Master GM34-CWQ2 holds up in terms of input lag after doing 100 iterations of the input lag test.



The Cooler Master GM34-CWQ2 shows an average input lag of around 3.05 milliseconds, which is an excellent result for a gaming monitor. Such low input lag can't be picked up even by the most hardcore gamers, including esports professionals. Cooler Master managed to halve the input lag of the GM34-CWQ2 compared to its predecessor.