Gaming Performance

To make the most of a 240 Hz panel, you'll want to combine it with a gaming rig that can hit 240 frames per second in the games you're playing, or at least as close to that as possible. This is important for the best-possible accuracy, lowest input lag, and sharpest moving visuals. These are also the main reasons why you're buying a gaming-grade monitor in the first place, so before anything else, make sure you have a PC that can hit high framerates. Buying this monitor and playing at 60 FPS would be a waste of money. Remember, when you're using G-Sync (or FreeSync), the buttery smoothness of the action is achieved by keeping the refresh rate of the monitor in perfect sync with the in-game framerate. Meaning, if you're playing at 60 FPS, the panel will refresh at 60 Hz and you simply won't experience all those wonderful benefits of gaming at high refresh rates.

Since the MSI Oculux NXG251R uses a Full HD panel, any higher-end GeForce GTX or RTX graphics card will allow you to hit those sweet high framerates at that resolution. You shouldn't go below a GTX 1080 or RTX 2070 unless you're playing an extremely undemanding game.

Overall gaming performance of the MSI Oculux NXG251R is terrific. I tested it on a beefy PC (Core i9-9900K and MSI GeForce GTX 1080 Ti Gaming X Trio) and had a blast in Apex Legends, Battlefield V, CS:GO, PUBG, and anything else I threw at it. The smoothness of the action is sublime, and the responsiveness of the monitor is superb. My "usual" gaming monitor is equipped with a 165 Hz G-Sync panel, so I was interested to see if I would notice a perceptible difference between playing at 165 and 200+ FPS/Hz. Even though I can't say I felt a huge (or any) difference in terms of general responsiveness and aim accuracy, what stood out was the sharpness of fast-moving images, which is noticeably higher at 200+ Hz than at 144 or 165 Hz. I was later able to verify this with my pursuit camera tests, which you can find below. Generally, the jump from 144/165 Hz to 240 Hz is nowhere as drastic of one as from 60 Hz to 144 Hz, but if you're looking to put yourself on the bleeding edge of today's competitive gaming, it makes sense to go down this route. In case you're still using a 60 Hz monitor, switching to the MSI Oculux NXG251R will be downright revolutionary—the single biggest possible upgrade to your overall gaming experience. Of course, the same could be said of any other good 240 Hz gaming monitor as they generally tend to use the same technology, which has them behave similarly (in terms of input lag and pixel responsiveness).

Response Time and Overdrive

The MSI Oculux NXG251R has a 1 ms GtG response time. The panel uses overdrive technology to make pixel transitions faster. Its options can be found under "Response Time" in the OSD (Gaming menu). Response Time can be adjusted to one of three available settings: Normal, Fast, and Fastest.


I extensively tested all of them by using the so-called pursuit camera method developed by the good people of Blur Busters, namely Mark D. Rejhon. The idea of the procedure is to use a standard DSRL camera to capture the motion blur exactly as your eyes see it. This is achieved by mounting a camera on a smooth slider, setting the camera exposure to four times the length of the monitor refresh rate and loading the Ghosting Test Pattern with the Pursuit Camera Sync Track invented by Mark Rejhon of Blur Busters. Then, the camera has to be slid sideways at the same speed as the on-screen motion. The sync track is there to tell you if you're moving the camera too fast or too slow, or if it shakes too much. The procedure takes some practice and getting used to, but yields great results and lets us examine the differences between various overdrive settings at various monitor refresh rates.

I made a series of photos at refresh rates of 60, 100, 144 and 240 Hz, at all three available overdrive settings. Let's take a look at the results and figure out what the ideal overdrive setting would be.



It's quite obvious that the best Response Time setting is "Fast". This is what the monitor is set to by default, and you shouldn't change it. Setting the Response Time to "Fastest" introduces quite a lot of overshoot at all refresh rates, while the "Normal" setting is noticeably blurrier than "Fast".

Input Lag

I use a high-speed camera and a modified gaming mouse to measure the input lag of a monitor. Below is a detailed explanation of my testing procedure. Being aware of it is important in interpreting the results properly.

I start by connecting a modified gaming mouse, the Logitech G9x, to my PC. The mouse has a blue LED connected directly to its primary button, which instantly illuminates after pressing the button. The USB sample rate is set to 1,000 Hz via the Logitech Gaming Software. Then, I mount the Nikon 1 J5, a mirrorless camera capable of recording video in 1,200 FPS, in front of the monitor. After that, I run Counter Strike: Global Offensive and load a custom map (Map_Flood, made by a member of the Blur Busters community) consisting of nothing but a huge white square suspended in a black void. The camera is set up in a way that records the entire screen.

Every video setting in CS:GO is either switched to the lowest possible setting or turned off, and a console command "fps_max 0" is used to turn off the built-in FPS limiter and get as many frames per second as possible. The purpose of that is to remove the input lag caused by the game engine from the equation. My system is equipped with an overclocked Core i7-6700K and a GTX 1080 Ti, so it has no trouble hitting 2,000 FPS in that scenario. Vertical Sync and G-Sync/FreeSync are also turned off because we don't want anything delaying the drawing of the frames—our goal is to have the first frame reach the screen as fast as the monitor itself lets it rather than limiting it by various syncing methods. You're probably wondering how much additional input lag is introduced when G-Sync or FreeSync is used, which is undoubtedly something every user of a monitor that supports it will use as it is the reason you're buying it in the first place. I tested several different G-Sync and FreeSync monitors extensively with G-Sync/FreeSync on and off and found that G-Sync/FreeSync introduces an additional 2 ms of input lag on average.

The test is conducted by starting the video recording and pressing the left mouse button, which is bound to the in-game command "Strafe Left", after which the LED blinks and an in-game movement occurs. I repeat this twenty times and then open the recorded videos in QuickTime, which has the nice option of browsing through a video frame by frame. I then find the frame where the LED first turned on and carefully look for the frame where the first glimpse of on-screen movement occurs. The exact number of frames it took between those two events is then multiplied by 0.8333 because I'm recording in 1,200 FPS (1 frame = 0.8333 ms). To get the final result, I subtract 5 ms from the calculated time because that's the average click latency of the Logitech G9x (between 4 and 6 ms). There are a couple of other factors that slightly influence the score, such as the LED reaction time (1 ms or less), camera lag (1 ms), and USB polling rate (1 ms), but those aren't constants, so I'm not subtracting them from the calculated final result. That's also one of the reasons why I'm taking as many as twenty measurements—the impact of the aforementioned error margins is reduced with each taken sample.

In the end, we get the so-called button-to-pixel lag value: the time that passes from when you perform an action with your mouse and said action is first registered on screen. Anything below 16 ms (equals one frame of lag at 60 Hz) can be considered gaming-grade, and such a monitor is suitable for even the most demanding gamers and eSports professionals. If the input lag falls between 16–32 ms (between 1–2 frames of lag at 60 Hz), the monitor is suitable for almost everyone but the most hardcore gamers, especially if they're playing first-person shooters on a professional level. Finally, if a monitor's input lag is higher than 32 ms (over 2 frames of lag at 60 Hz), even casual gamers should be able to notice it. Will they be bothered by it? Not necessarily, but I can't recommend a screen like that for serious gaming.

Here's how the MSI Oculux NXG251R holds up in terms of input lag:



As we can see by looking at the numbers, the MSI Oculux NXG251R offers excellent gaming performance. Minimum input lag was as low as 5 ms and never went above 13.33 ms, with an average of 10.09 ms. This truly is a gaming-grade monitor perfectly capable of meeting the high demands of eSports professionals.

ULMB

ULMB (Ultra Low Motion Blur) is a technology enabled by NVIDIA's G-Sync module, but one that can't be combined with it because it works at a fixed refresh rate. In other words, it's either G-Sync or ULMB. It tries to annihilate the blur by having the backlight act as a strobe. However, if not implemented properly, it can introduce flickering. It also has a few other caveats. If you want to use ULMB, you'll have to first disable G-Sync and lower the refresh rate to 100, 120, or 144 Hz. Only then can it be turned on in the OSD. After you do, you'll notice that the brightness of the screen takes a hit.

The exact strength of that hit varies from monitor to monitor. Sometimes, ULMB makes the screen so dark it's rendered unusable. This isn't the case with the MSI Oculux NXG251R, though. It actually has one of the better ULMB implementations I have come across as the picture is never too dim, even for combined daytime and nighttime usage. In exact numbers, adjusting the brightness to 100 in the OSD and activating ULMB at a refresh rate of 144 Hz will result in an actual screen brightness of 246.12 nits. Things get even better as you lower the refresh rate since the backlight doesn't have to strobe as much. At 120 Hz, brightness goes up to 264.57 nits, and all the way up to 319.53 nits at 100 Hz. Even so, I'd keep away from ULMB and stick with the "regular" 240 Hz refresh rate since the motion blur reduction with ULMB isn't perfect, as you can see in these pursuit camera photos (click on the picture to see it in full resolution).



Overall, I suggest you simply forget about it and stick with G-Sync. That way, you get a much brighter, vivid picture, more smoothness, and a higher refresh rate without a significant increase in perceived motion blur. With that in mind, I can't think of a single reason why you'd want to use ULMB with this monitor.