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AOC AG251FZ 240Hz FreeSync Monitor Review

OSD Setup & Calibration

The AG251FZ’s OSD is AOC’s familiar strip system that appears along the bottom of the screen. You can move it around if you wish, but it makes the most sense in its default position. One bit of trivia we noticed: As the refresh rate goes up, the menu becomes more responsive. At 240Hz we were literally ripping through it!

The Luminance menu has contrast and brightness sliders along with six picture modes. Standard is fine for any application, and as long as the Gaming modes are disabled, you can adjust all image parameters. There are three gamma presets, each of which has a slightly different look. We’ll cover them on page four.

Image Setup has everything you need to adjust geometry for analog signals. You get clock, phase, sharpness and positioning options.

The Color Setup menu is just like the one found in every AOC monitor. There are four color temp presets, one of which is labeled sRGB. It’s reasonably accurate, but it locks out all other picture controls including brightness. Output is then fixed at around 290cd/m2. The Warm setting is the best of the rest, or you can calibrate User with a precise set of RGB sliders. The only caveat is that you must choose a gamma preset first. Each one imparts a slightly different color temp and therefore requires different RGB values.

Like all AOC monitors, the AG251FZ has Picture Boost. By turning on the Bright Frame option, the user can create a window of any size and position on the screen. Brightness and contrast can then be adjusted only within that space. It’s a handy way to focus on a particular part of the image.

OSD Setup offers multiple language options, a timeout of up to 120 seconds, horizontal and vertical positioning, and transparency level. You can set a break reminder that will flash an on-screen message after one hour. If you need backward compatibility with DisplayPort 1.1, that option is here. Finally, there is a volume slider for the internal speakers and headphone output.

The Game Setting menu is only found on Agon-series displays. It offers three preset modes plus three additional user memories. Once you’ve dialed in the AG251FZ, settings can be saved to these slots and recalled with one of the numbered controller buttons. We suggest leaving this turned off. It turns on some options and locks out others, all of which affect image quality. Our best result was with a traditional calibration in the Standard Eco mode.

Shadow Control is a way to increase dark-level detail and should be left on its default setting of 50. Low Input Lag decreases latency by turning off the frame buffer. The option is grayed out in FreeSync mode. Game Color is a general saturation control that affects the entire gamut. It also should be left on its default setting of 10. Low Blue Light has three options (weak, medium, and strong) that serve to reduce eye fatigue by warming the color temp. The overdrive also has three levels and works best on the medium setting.

The Extra menu has an input selector, 0-24-hour off timer, aspect ratio control, DDC/CI toggle, and a factory reset. On the right side is basic signal information. In FreeSync mode, the V Frequency field appropriately says “FreeSync.” Otherwise, it states the refresh rate, up to 240 Hz.


The AG251FZ is fairly accurate out of the box with good grayscale tracking and low color gamut errors. The easiest way to go is to select the Gamma 2 preset and set brightness to taste. If you plan to calibrate as we did, select the User color temp. That option requires some adjustment, although a precise set of RGB sliders makes that fairly easy. Be sure the Game Modes are turned off before making any changes. With a few adjustments, some small gains are possible. Check out our recommended settings if you’d like to tweak your AG251FZ.

AOC AG251FZ Calibration Settings
Eco ModeStandard
Game ModeOff
Shadow Control50
Game Color10
Brightness 200cd/m244
Brightness 120cd/m217
Brightness 100cd/m210
Brightness 80cd/m24
Color TempRed 52, Green 52, Blue 49

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Christian Eberle
Christian Eberle is a Contributing Editor for Tom's Hardware US. He's a veteran reviewer of A/V equipment, specializing in monitors.