AOC AG251FZ Review

Box Design, Setup & Extras

The AG251FZ comes in a big box that stands out with eye-catching graphics highlighting its gaming features. You’ll see the impressive 240 Hz refresh rate and the FreeSync logo clearly displayed, along with other cool specs. When you open it up, you'll need to put together the panel and stand using four Philips-head screws. After that, just attach the base with a captive bolt. The overall build quality is a step up from AOC's usual standard, which is already quite impressive.

The power supply comes as an external unit in a big brick. You’ll find HDMI and DVI video cables included, but oddly, there’s no DisplayPort cable. The accessory pack also has a USB 3.0 cable and a metal adapter for the VESA mount, which is essential if you want to set up a wall bracket or monitor arm. Drivers and manuals are provided on a CD-ROM.

Product Overview

The display features a slim bezel, measuring just 12mm on the top and sides. It doesn’t claim to be a zero-frame design, but the minimal borders still provide a clean look. The bottom bezel is a bit thicker at 20mm. You won't face problems with reflections from surrounding light on this screen. It effectively reduces glare and maintains great clarity without any noticeable grain.

You’ll find the controls on the bottom right of the screen, but you probably won't need to use them much except for the power button. The package comes with a stylish wired controller that lets you navigate the on-screen display easily and features three buttons for different image modes.

The base and upright are crafted from durable aluminum, providing excellent stability when assembled. You can adjust the height by 4.5 inches, with a 20° swivel on each side, a 21.5° backward tilt, and a 3.5° forward tilt. Plus, there's an option for portrait mode. All adjustments feel premium, and there's a handy scale on one side to help you easily replicate the panel's vertical position.

The side profile is moderately thick, featuring two USB ports and mic and headphone outputs on the right edge. Just above them, there's a handy hook that swings out for hanging your headphones. The Agon design theme carries on at the back with a striking red trim that has a brushed-metal finish. At the top, two speakers are positioned behind small, upward-facing grills. They provide decent volume without much distortion. Their 3W rating is slightly higher than average. Overall, this setup clearly shows it’s built for gaming without going for the flashy sci-fi aesthetic found in other high-end monitors.

The input options on this monitor are top-notch, even better than many G-Sync models. It features a DisplayPort along with HDMI 1.4 and 2.0 ports. The HDMI 2.0 supports FreeSync, 240Hz refresh rates, and HDCP 2.2, while HDMI 1.4 is compatible with MHL devices. There’s also a DVI port that can handle up to 144 Hz and a VGA connection for 60 Hz support. Additionally, you’ll find extra USB ports, an analog audio input, and a mic input. The mini-USB port is designated for the OSD controller.

Specs

I recently found out that AU Optronics created this new component with Nvidia's help. What better way to demonstrate adaptive sync than with a top-notch display? The AG251FZ performs smoothly at up to 240 Hz without needing to overclock through the on-screen settings. Just pick the refresh rate from Windows’ display options, and you’re all set. It supports FreeSync from 48-240 Hz, which is different from the G-Sync panel that runs from 24-240 Hz. Honestly, at FHD resolution, no one should settle for framerates below 48. Even an entry-level graphics card can push this monitor beyond that.

This monitor doesn't feature any blur-reduction tech. Given the high speeds it can handle, that isn't a major concern for us. Many top-tier players favor ULMB over G-Sync or Freesync, but in our testing, we've found that G-Sync and Freesync provide a smoother gaming experience. Still, AOC maximizes the brightness potential of this panel, reaching up to 400nits in our tests. Later on, we'll share some notable response and lag statistics as well.

This is definitely going to be the fastest monitor for AMD gamers. However, it also needs to provide accurate colors, good contrast, and smooth motion handling. Our benchmark tests will reveal everything. Let’s dive in.

Setting Up and Calibrating OSD

The AG251FZ features AOC’s well-known on-screen display (OSD) that runs along the bottom of the screen. You can adjust its position if you want, but it's best to leave it where it is by default. A cool detail we found is that as the refresh rate increases, the menu responds faster. At 240Hz, we were zooming through the options!

The Luminance menu features sliders for contrast and brightness, plus six different picture modes. The Standard mode works well for all uses, and with Gaming modes turned off, you can tweak all the image settings. There are three gamma presets, each offering a unique visual style. We’ll dive deeper into these on page four.

Image Setup offers all the tools you need to tweak the geometry for your analog signals. You can adjust the clock, phase, sharpness, and positioning to get the perfect display for your CS2 gameplay.

The Color Setup menu resembles the ones on all AOC monitors. It offers four color temperature presets, including one called sRGB. This preset is fairly accurate but restricts access to other picture settings like brightness, fixing the output at about 290cd/m2. The Warm setting is the top choice among the others, or you can customize the User setting using the RGB sliders. Just remember, you need to select a gamma preset first, as each option affects the color temperature and requires different RGB values.

The AOC AG251FZ monitor features Picture Boost, just like other AOC models. By enabling the Bright Frame option, players can set a custom window of any size and position on their screen. This allows for adjusting brightness and contrast specifically within that area. It's a useful tool for highlighting key parts of the action.

OSD Setup includes several language choices, a timeout feature that goes up to 120 seconds, and options for both horizontal and vertical placement, along with transparency settings. You can also set a break reminder that will show a message on your screen after an hour of play. For those needing backward compatibility with DisplayPort 1.1, that's available too. Plus, there’s a volume slider for adjusting the internal speakers and headphone output.

The Game Setting menu is available exclusively on Agon-series monitors. It features three preset modes along with three custom memory slots. After you set up the AG251FZ, you can save your configurations to these slots and access them using the numbered controller buttons. We recommend keeping this option off. When activated, it enables some settings while disabling others, which can impact image quality. Our top performance came from a standard calibration in Standard Eco mode.

Shadow Control enhances detail in darker areas and is best kept at its default level of 50. Low Input Lag minimizes latency by disabling the frame buffer, but this option is not available in FreeSync mode. Game Color adjusts the overall saturation and should remain at its default setting of 10. Low Blue Light offers three levels (weak, medium, and strong) to help alleviate eye strain by warming the color temperature. The overdrive feature has three settings as well, with medium being the most effective.

The Extra menu features an input selector, a 0-24 hour off timer, aspect ratio settings, a DDC/CI toggle, and a factory reset option. On the right, you’ll find essential signal info. When in FreeSync mode, the V Frequency section displays “FreeSync.” If not in that mode, it shows the refresh rate, which can go up to 240 Hz.

Calibration in CS2 is a crucial process that helps set your skill level in competitive matches. When you first jump into ranked play, you'll need to complete a series of placement matches. These games assess your performance and determine your initial rank. It's important to play consistently, as your results during calibration will impact your long-term ranking. Focus on teamwork, communication, and mastering your aim to achieve the best possible outcome during this phase. Remember, calibration is just the beginning of your journey in the competitive scene!

The AG251FZ monitor works well for gaming right away, offering solid grayscale tracking and minimal color errors. For the best experience, pick the Gamma 2 preset and adjust the brightness to your liking. If you want to calibrate it like we did, choose the User color temperature. This option needs some tweaking, but the RGB sliders make it manageable. Just remember to turn off Game Modes before making any adjustments. With a few tweaks, you can achieve slight improvements. Take a look at our suggested settings if you want to optimize your AG251FZ for CS2.

Uncalibrated – Highest Brightness Setting

Usually, we categorize monitors based on price, size, or type. But today, we’re focusing on speed. We’ve searched our database for the quickest monitors and selected the latest models for this comparison. Asus brings in the PG258Q. Acer contributes with the XB252Q and Z301C. The AOC AG271QG joins the lineup, along with Dell’s S2417G. All these monitors boast high refresh rates, minimal panel response times, and incredibly low input lag, perfect for CS2 gameplay.

For gamers, having a monitor that shines brightly is crucial for reducing motion blur, especially with backlight strobe technology that can dim the display. The AG251FZ skips this feature but still offers impressive brightness, reaching almost 400cd/m2. While most players might not require such high brightness, the panel is set up for potential future blur-reduction enhancements from AOC.

TN and IPS screens perform similarly when it comes to black levels and contrast. We aim for at least a 1000:1 ratio, and the AG251FZ meets that target. It's great to highlight the inclusion of an AMVA display here, as it offers nearly three times the contrast of the next best option. With 240 Hz now a standard feature, it would be nice to see manufacturers focus on improving dynamic range even more.

Uncalibrated – Lowest Backlight Setting

The backlight dims to a comfortable 68.9614cd/m2, making it suitable for playing in dark environments. The black level ranking falls to fourth, but that's just because the other displays can achieve lower brightness. The contrast stays strong at third place with a steady 1002.7:1 ratio.

Following Calibration to 200cd/m2

When it comes to calibrating the AG251FZ, it just edges out the PG258Q in the black-level test. Since both monitors use the same core panel, this is expected. We've seen no drop in performance here, while other monitors might lose a bit of contrast. The improvements in color accuracy are minor, but with a few tweaks, the results can be well worth it.

ANSI Contrast Ratio in Counter-Strike 2

The ANSI test has dropped the AOC to third place, but it still stands strong against the competition. Even with its classic TN tech, the AU Optronics panel here is a fresh component built to high standards. When you combine that with its incredible speed, it elevates your gaming experience in CS2 to new heights.

Shades of Gray, Brightness & Hues

The AG251FZ gives players solid choices for setting up their visuals. In Standard Eco mode with Game Mode turned off and color temperature set to Warm, you'll achieve good performance without needing extensive calibration. If you're aiming for that final tweak, switch to User mode and adjust the RGB sliders as we recommend. Don't forget to tweak the gamma settings as we'll explain.

Grayscale Tracking is a game mechanic in Counter-Strike 2 that enhances player visibility and tracking. It provides a unique way to see opponents by emphasizing their silhouettes against various backgrounds. This feature can help players better anticipate enemy movements and improve their reaction times during intense gameplay.

We’ve detailed our grayscale and gamma tests right here.

When you look at the first and fourth charts, the difference is pretty minimal. Right out of the box, the AG251FZ performs well but has a slight purple tint at full brightness. This minor issue doesn’t bump it off the “no calibration needed” list. Overall, this monitor does a solid job. If you pick the sRGB color temp preset, it shifts to a warmer tone with a reddish hue throughout. Choosing the User setting means you’ll need to calibrate it, as the default setting can appear too blue. Grayscale isn’t a problem here; our main focus is on gamma, which we'll dive into next.

Matchups

Gaming monitors often struggle with color accuracy, particularly when they haven't been calibrated. However, the AG251FZ defies this trend with an impressive default score of 1.11dE. Even after our tweaks, we saw only a slight improvement, which solidifies this monitor's spot on our "most accurate" list. There are definitely some professional screens that could take advantage of this level of quality.

Gamma Reaction

Gamma tracking presents some challenges with the AG251FZ monitor. After testing various settings, we found that achieving perfect tracking at the 2.2 level is not possible. The initial chart suggests that lowering the contrast slider is necessary. This adjustment improved the grayscale but didn’t change the gamma. Using the sRGB preset resulted in the middle and lighter tones appearing darker, while the darkest tones became more pronounced. Overall, this led to a decrease in perceived contrast, which can impact visibility in CS2.

In User mode, the RGB adjustments worked well with the Gamma 2 preset. While shadow details might appear a bit too bright, some players might actually like that. Most brightness levels are pretty much on point for a good visual experience. The final chart displays the Gamma 3 setting, which is noticeably too dark. On a monitor with a 1000:1 contrast ratio, the image looks muddy and lacks depth.

Comparative Analysis

The AG251FZ falls short in performance. Its tracking isn't as precise compared to the other monitors. While the difference may seem minor, it's noticeable when viewed side by side. In average value tests, the AOC performs better, maintaining its brightness levels around the 2.2 mark.

Color Range and Brightness

Fortunately, our not-so-great gamma scores don't significantly affect the accuracy of colors and brightness. The AG251FZ's color settings closely align with the sRGB standard. In its default mode, it has an average error of just 2.37dE, which is quite impressive. Switching to the sRGB preset raises that error slightly to 2.75dE, so there's not much difference. In User mode, we managed to lower the error to 1.87dE. The only color that gives us trouble is red, which is a bit lacking in saturation. Our tweaks mainly focused on balancing brightness levels, resulting in a noticeable boost in color quality.

Sight Lines

We all know that viewing angles are a major weakness for TN panels. They just can't compete with IPS and VA technologies. However, newer TN panels have shown slight improvements in quality. While the red color shift is still noticeable at wider angles, the AG251FZ does a better job of keeping dark details intact compared to older models. Many TN monitors tend to merge the lower brightness levels, specifically at 0, 10, and 20% brightness. You can see all the brightness steps from the top, but the dynamic range is still not as good as it could be. As long as these monitors stay under 27 inches, they will be decent choices. But with IPS and VA panels getting closer in speed, TN technology might soon become obsolete.

Visual Consistency

Screen uniformity is a specific issue that depends on the individual monitor, not the technology itself. It's important not to assume that IPS panels are worse based on current findings. We're really impressed with the quality control from AU Optronics' latest model, which has excelled in our black field test. The AG251FZ has achieved one of the lowest values ever recorded at just 3.47% for black and 3.75% for white. These figures are well below the visible threshold, and the color error variation is only 1.47dE. It doesn't get much better than this.

Pixel Reaction and Input Delay

If you want to know about a top-notch monitor for CS2, check out the AG251FZ. It’s one of the fastest monitors we've tested. When it comes to response time, there’s not much difference between six and seven milliseconds. However, input lag is crucial, and AOC really shines here. This test was done in FreeSync mode, so the Low Input Lag feature was turned off. The monitor needs to use its frame buffer for adaptive-sync, but there’s no downside to choosing AMD over Nvidia in this situation. Only Asus is ahead of AOC in this area. If you’re after the best control response in a FreeSync monitor, this is the one to get.

Playing with FreeSync

Our AMD test setup is running a bit slow with the Radeon R9 285, but even while playing CS2 on high settings, we consistently see over 65 FPS during intense firefights. In less chaotic moments, we can reach up to 80 FPS. While this isn’t nearly what the AG251FZ can handle, the gameplay remains enjoyable. FreeSync is fully functional, and with the Medium overdrive setting, motion feels incredibly smooth. The standout feature is the responsive control, giving you that ESP-like precision. You won’t notice any lag with this monitor. Although we may sacrifice some resolution, the speed makes a significant difference. Even if you’re not hitting 240 FPS, a monitor like this can greatly enhance your gaming experience.

Jumping into Counter-Strike 2 quickly shows that playing below 48 FPS isn't ideal. Even though the AG251FZ has low framerate compensation (LFC) due to its broad refresh rate, we noticed a rise in input lag right away. This processing can add some control delay. Luckily, when we switched our settings from Ultra to Very High, our system performed much better. With FPS hitting over 70, we regained confidence in the monitor—thanks to its FHD resolution. Keep in mind that CS2 is a demanding game, pushing even the best hardware to its limits with its intricate graphics.

While our setup may seem basic by current benchmarks, the AG251FZ proves it stands strong against G-Sync monitors. When pushed to higher speeds, it delivers an incredibly smooth gaming experience, unmatched by any other.

Key Elements & Details

A couple of months back, we took a look at the ROG Swift PG258Q, Asus's first 240 Hz monitor. This display gives competitive players a serious edge with G-Sync, ULMB, lightning-fast panel response, and nearly zero input lag. However, it comes with a steep price, higher than other 25” FHD monitors. A chunk of that cost is due to the G-Sync module, which adds about $120 to the total.

Today, we’re checking out the FreeSync version of a gaming monitor from AU Optronics, the AOC AG251FZ. This monitor is part of the Agon series and features the same impressive 240 Hz refresh rate, perfect for fast-paced gameplay. It supports adaptive sync for AMD users but doesn't include any blur reduction tech. Priced around $450, it’s a more budget-friendly option. Like the PG258Q and Acer’s XB252Q, it keeps that high speed while running at 1920x1080 resolution. Some might think this is a downgrade, but seeing it in action might change your perspective.

In summary

When 25” 240 Hz monitors hit the market for over $500, we were curious if they would just be a passing trend. The AOC AG251FZ is the third monitor of this kind we’ve tested, and after seeing their impressive gaming performance, we believe they’re here to stay. With G-Sync often costing more, it was only a matter of time before brands started catering to FreeSync users too. When the hardware is on par, it’s nearly impossible to notice a difference between the two. G-Sync provides more reliable specs across different panels, but with the right choice, AMD can offer the same great experience.

AOC is making waves in the gaming scene. With the launch of the Agon series, they’re stepping up to challenge big players like Asus ROG and Acer Predator, who have long dominated the market.

The AG251FZ does save you around $120, but you lose features like adaptive sync down to 24 Hz and blur-reduction. For FHD resolution, the refresh rate isn’t a big deal. If you’re spending over $400 on a gaming monitor, you probably aren’t using a slow PC. Even a budget graphics card can easily exceed 60 FPS on this display. By tweaking detail settings, you can easily hit over 100 FPS without much hassle.

During our testing of G-Sync monitors for CS2, we noticed that using ULMB usually leads to a decrease in brightness. While you lose adaptive sync, the backlight strobe does impact performance; however, newer monitors have a smaller effect. This can be avoided if the monitor can output enough brightness, like the AU Optronics 24.5” model we're using. Nonetheless, some players believe that ULMB can reduce input lag. We haven't been able to confirm that, as our tests indicate that the AG251FZ is just as responsive as its G-Sync counterparts.

Color performance might not top the list for gamers, but our testing showed that this monitor performed well. Most players will be happy with the AOC straight out of the box. If you choose not to calibrate, we recommend at least trying the Gamma 2 setting. The factory settings for gamut and grayscale tracking are well-tuned. Plus, our sample displayed impressive uniformity, better than almost any monitor we’ve evaluated.

If you're still relying on the AG251FZ's FHD resolution and TN display, we highly recommend giving it a shot before making any decisions. The specs might look outdated at first glance, but the gaming experience is truly exceptional. You'll feel like the system is anticipating your moves, with each command leading to immediate action. The visuals connect seamlessly with your gameplay, almost as if they're an extension of your own hands.