AOC CU34G2X Monitor Review

Tested using Methodology v1.1
Reviewed Jul 13, 2021 at 09:51 am
AOC CU34G2X Picture
7.8
Mixed Usage
7.7
Office
8.3
Gaming
7.7
Multimedia
7.9
Media Creation
7.2
HDR Gaming
Size 34"
Resolution 3440x1440
Max Refresh Rate
144 Hz
Pixel Type
VA
Variable Refresh Rate
Adaptive Sync

The AOC CU34G2X is a great ultrawide gaming monitor. It has a 144Hz panel with Adaptive Sync support, so even though it's not officially certified by AMD nor NVIDIA for variable refresh rate (VRR) support, FreeSync and G-SYNC still both work on it. It has low input lag, and although it has a quick overall response time, there's visible black smearing, which is typical of VA panels. Speaking of which, it has a high native contrast ratio, but that means it has narrow viewing angles, so it's not ideal for co-op gaming. The 34 inch screen and 3440x1440 resolution help deliver an immersive gaming experience, and it has a fairly aggressive 1500R curve to bring the edges of the screen within your field of vision.

Our Verdict

7.8 Mixed Usage

The AOC CU34G2X is a good overall monitor. It's great for gaming because it has a 144Hz refresh rate, FreeSync and G-SYNC compatibility, and low input lag, but there's visible black smearing. It's good for office use or content creators thanks to its large screen and good text clarity, but it has narrow viewing angles. Unfortunately, even though it has a good contrast ratio, it doesn't deliver a satisfying HDR experience because it doesn't get bright enough to make highlights pop.

Pros
  • 34 inch screen and 3440x1440 resolution deliver immersive experience.
  • Tilt, swivel, and height adjustments.
  • 144Hz refresh rate with VRR support.
  • Good native contrast ratio.
Cons
  • Narrow viewing angles.
  • Noticeable black smearing with fast-moving objects.
  • No local dimming feature.
7.7 Office

The AOC CU34G2X is good for office use. The large 34 inch screen allows you to open multiple windows side-by-side, and it delivers clear text thanks to its high resolution. It's decent to use in a well-lit room, but it doesn't get bright enough to fight a ton of glare. Also, it has narrow viewing angles, so it's not ideal for sharing your screen with others.

Pros
  • 34 inch screen and 3440x1440 resolution deliver immersive experience.
  • Tilt, swivel, and height adjustments.
  • Decent reflection handling for a moderately-lit room.
Cons
  • Narrow viewing angles.
  • Not bright enough to fight glare from strong light sources.
8.3 Gaming

The AOC CU34G2X is impressive for gaming. It has a high 144Hz refresh rate with G-SYNC and FreeSync compatibility that you can achieve over a DisplayPort connection. It has low input lag and a fairly quick response time, but like other VA panel monitors, there's noticeable black smearing. It's great for dark room gaming as it has high contrast, but it lacks a local dimming feature.

Pros
  • Tilt, swivel, and height adjustments.
  • 144Hz refresh rate with VRR support.
  • Low input lag.
  • Good native contrast ratio.
Cons
  • Noticeable black smearing with fast-moving objects.
  • No local dimming feature.
7.7 Multimedia

The AOC CU34G2X is good for watching multimedia content. The large screen provides an immersive viewing experience, and the 21:9 aspect ratio is good for watching movies. It has a high contrast to deliver fairly deep blacks, but there's no local dimming feature. It's not the best for sharing your screen with a friend as it has narrow viewing angles.

Pros
  • 34 inch screen and 3440x1440 resolution deliver immersive experience.
  • Tilt, swivel, and height adjustments.
  • Good native contrast ratio.
Cons
  • Narrow viewing angles.
  • No local dimming feature.
7.9 Media Creation

The AOC CU34G2X is very good for content creators. The large screen space makes it easy to see your entire video timeline without scrolling too much, and the 3440x1440 resolution helps deliver crisp images. It has decent ergonomics if you need to place the screen in an ideal position, but it has narrow viewing angles, making it harder to share the screen with a coworker or client.

Pros
  • 34 inch screen and 3440x1440 resolution deliver immersive experience.
  • Tilt, swivel, and height adjustments.
  • Decent reflection handling for a moderately-lit room.
Cons
  • Narrow viewing angles.
  • Not bright enough to fight glare from strong light sources.
7.2 HDR Gaming

The AOC CU34G2X is decent for HDR gaming. It has great gaming features like a 144Hz refresh rate, VRR support, and low input lag. It displays deep blacks due to its high contrast, but it doesn't have a local dimming feature. HDR content doesn't look too different from SDR because it has a limited color gamut and doesn't get bright enough to make highlights pop.

Pros
  • 144Hz refresh rate with VRR support.
  • Low input lag.
  • Good native contrast ratio.
Cons
  • Noticeable black smearing with fast-moving objects.
  • No local dimming feature.
  • Low HDR peak brightness.
  • 7.8 Mixed Usage
  • 7.7 Office
  • 8.3 Gaming
  • 7.7 Multimedia
  • 7.9 Media Creation
  • 7.2 HDR Gaming
  1. Updated Jul 13, 2021: Review published.
  2. Updated Jul 09, 2021: Early access published.

Test Results

perceptual testing image
Design
Design
Style
Curved Yes
Curve Radius 1500R
Weight (without stand)
14.6 lbs (6.6 kg)
Weight (with stand)
18.3 lbs (8.3 kg)

The AOC CU34G2X has a gamer-oriented design with black plastic and red accents throughout. It has a fairly aggressive curve to help bring the edges within your field of vision. The stand and the screen itself have large footprints, so you'll need a big desk to place the monitor on.

Design
Stand
Width
21.3" (54.0 cm)
Depth
10.0" (25.4 cm)

The stand has a large footprint, and there's a fair amount of wobble from the screen. It looks like a tripod stand from the front, but there are two feet in the back.

7.0
Design
Ergonomics
Height Adjustment
5.5" (14.0 cm)
Switch Portrait/Landscape No
Swivel Range -35° to 35°
Tilt Range -25° to 2.5°

The AOC CU34G2X has decent ergonomics. You can easily adjust it, except you can't rotate it into portrait mode, but that's expected from an ultrawide monitor.

Design
Back
Wall Mount VESA 100x100

The back is mainly black with a few red accents. There's a cutout in the stand that serves as cable management.

Design
Borders
Borders
0.4" (0.9 cm)
Design
Thickness
Thickness (with stand)
9.1" (23.1 cm)
Thickness (without stand)
3.9" (9.9 cm)

Due to the screen's curvature, it's fairly thick, and it takes up a good amount of space on a desk with the stand attached.

7.0
Design
Build Quality

The build quality is decent. It's made entirely out of solid plastic, and the stand feels stable when making ergonomic adjustments. However, the screen wobbles fairly easily on the stand, and the bottom bezel isn't properly attached to the screen throughout. The controls are really hard to press and even cause the screen to tilt a bit. Also, there are rubber grips at the bottom of the feet that come off easily.

Picture Quality
7.7
Picture Quality
Contrast
Native Contrast
2,789 : 1
Contrast With Local Dimming
N/A

The AOC CU34G2X has a good native contrast ratio that makes blacks look fairly deep. However, there's no local dimming feature to improve it. Keep in mind that contrast can vary between units.

0
Picture Quality
Local Dimming
Local Dimming
No
Backlight
Edge

The AOC CU34G2X 34 doesn't have a local dimming feature. The video is for reference only, so you can see how the backlight on this display performs and compare it to a similar product with local dimming.

7.0
Picture Quality
SDR Peak Brightness
SDR Real Scene
257 cd/m²
SDR Peak 2% Window
265 cd/m²
SDR Peak 10% Window
265 cd/m²
SDR Peak 25% Window
265 cd/m²
SDR Peak 50% Window
265 cd/m²
SDR Peak 100% Window
264 cd/m²
SDR Sustained 2% Window
265 cd/m²
SDR Sustained 10% Window
265 cd/m²
SDR Sustained 25% Window
265 cd/m²
SDR Sustained 50% Window
264 cd/m²
SDR Sustained 100% Window
264 cd/m²
SDR ABL
0.000

The AOC CU34G2X has decent brightness. It's lower than the advertised 300 cd/m² and may not be enough to fight a ton of glare. We even measured the brightness before calibration and didn't reach the advertised brightness.

We measured the brightness after calibration in the 'Standard' Eco Mode with the Color Temperature set to 'User', and Brightness at its max.

5.7
Picture Quality
HDR Peak Brightness
HDR Real Scene
260 cd/m²
HDR Peak 2% Window
258 cd/m²
HDR Peak 10% Window
258 cd/m²
HDR Peak 25% Window
259 cd/m²
HDR Peak 50% Window
259 cd/m²
HDR Peak 100% Window
259 cd/m²
HDR Sustained 2% Window
258 cd/m²
HDR Sustained 10% Window
258 cd/m²
HDR Sustained 25% Window
259 cd/m²
HDR Sustained 50% Window
259 cd/m²
HDR Sustained 100% Window
259 cd/m²
HDR ABL
0.000

The HDR brightness is disappointing. It doesn't get brighter than in SDR, and it's not enough to make highlights stand out the way the creator intended. We measured it in the 'Game' HDR Mode and the brightness was about the same with the 'Picture' and 'Movie' modes.

6.4
Picture Quality
Horizontal Viewing Angle
Color Washout From Left
35°
Color Washout From Right
36°
Color Shift From Left
61°
Color Shift From Right
64°
Brightness Loss From Left
41°
Brightness Loss From Right
42°
Black Level Raise From Left
16°
Black Level Raise From Right
16°
Gamma Shift From Left
18°
Gamma Shift From Right
17°

The AOC CU34G2X has narrow horizontal viewing angles. It's better than most VA panel monitors, so the edges of the screen won't look too washed out if you sit close, and the curved screen helps with this, too, but we don't factor it into the testing. It still may not good enough for sharing your screen with others, though.

5.7
Picture Quality
Vertical Viewing Angle
Color Washout From Below
29°
Color Washout From Above
31°
Color Shift From Below
62°
Color Shift From Above
63°
Brightness Loss From Below
32°
Brightness Loss From Above
34°
Black Level Raise From Below
12°
Black Level Raise From Above
12°
Gamma Shift From Below
12°
Gamma Shift From Above
11°

Once again, the vertical viewing angles are disappointing. Although the colors don't shift much, there's still noticeable color washout, and the screen appears dimmer.

8.8
Picture Quality
Gray Uniformity
50% Std. Dev.
2.639%
50% DSE
0.091%
5% Std. Dev.
0.764%
5% DSE
0.043%

The AOC CU34G2X has excellent gray uniformity, but this can vary between units. Most of the screen looks fairly uniform, and there's almost no dirty screen effect in the center, which is great. Uniformity is better in near-dark scenes, but there's a bit of backlight bleed near the bottom.

6.7
Picture Quality
Black Uniformity
Native Std. Dev.
1.491%
Std. Dev. w/ L.D.
N/A

The black uniformity is okay. There's significant backlight bleed along the top and bottom edges, but there's almost no blooming around the center cross. Keep in mind that uniformity can vary between units.

8.2
Picture Quality
Pre Calibration
Picture Mode
Standard
Luminance
180 cd/m²
Luminance Settings
80
Contrast Setting
50
RGB Controls
50-50-50
Gamma Setting
Gamma 1
Color Temperature
6,266 K
White Balance dE
2.20
Color dE
2.46
Gamma
2.29

The out-of-the-box accuracy is great. Most colors are only slightly inaccurate, but not enough for most people to tell, and the same can be said about the white balance. Color temperature is on the warm side, but it's still close to the 6500K target. Unfortunately, gamma doesn't follow the target curve well as most scenes are darker than they should be.

There's an sRGB mode, but it results in a less accurate image:

  • Color Temperature: 6594K
  • White Balance dE: 4.35
  • Color dE: 2.83

9.6
Picture Quality
Post Calibration
Picture Mode
Standard
Luminance
99 cd/m²
Luminance Settings
59
Contrast Setting
50
RGB Controls
44-43-46
Gamma Setting
Gamma 3
Color Temperature
6,467 K
White Balance dE
0.48
Color dE
0.51
Gamma
2.19

The accuracy after calibration is fantastic. Any remaining white balance and color inaccuracies are impossible to spot by the naked eye, and color temperature is extremely close to the 6500K target. Gamma is improved, but some dark and bright scenes are slightly over-brightened.

You can download our ICC profile calibration here. This is provided for reference only and shouldn't be used, as the calibration values vary per individual unit, even for the same model, due to manufacturing tolerances.

9.1
Picture Quality
SDR Color Gamut
sRGB xy
97.8%
Adobe RGB xy
84.3%
sRGB Picture Mode
Standard
Adobe RGB Picture Mode
Standard

The SDR color gamut is fantastic. It has near-full coverage of the sRGB color space used in most web content and impressive coverage of the Adobe RGB color space used in photo editing.

9.4
Picture Quality
SDR Color Volume
sRGB In ICtCp
98.8%
Adobe RGB In ICtCp
89.6%
sRGB Picture Mode
Standard
Adobe RGB Picture Mode
Standard

The AOC CU34G2X has a remarkable SDR color volume. It can display colors at a wide range of luminance levels, except for extremely dark colors.

7.3
Picture Quality
HDR Color Gamut
Wide Color Gamut
Yes
DCI P3 xy
84.0%
Rec. 2020 xy
61.2%
DCI P3 Picture Mode
HDR Game
Rec. 2020 Picture Mode
HDR Game

The AOC CU34G2X 34 has a decent HDR color gamut. It has impressive coverage of the commonly-used DCI P3 color space, but the wider Rec. 2020 is limited.

Our measurement of the DCI P3 coverage is likely lower than other reviewers due to how we measure it. We measure it by sending a Rec. 2020 signal, but unlike most reviewers, we limit the colors to the DCI P3 primaries. This results in a lower but arguably more accurate measurement.

6.7
Picture Quality
HDR Color Volume
DCI-P3 In ICtCp
76.9%
Rec. 2020 In ICtCp
57.6%
DCI P3 Picture Mode
HDR Game
Rec. 2020 Picture Mode
HDR Game

The HDR color gamut is okay. It's a limited by the okay color gamut, and even has trouble displaying very dark colors despite its high contrast. It can't display really bright blues either, but that's typical of LED displays.

10
Picture Quality
Image Retention
IR After 0 Min Recovery
0.00%
IR After 2 Min Recovery
0.00%
IR After 4 Min Recovery
0.00%
IR After 6 Min Recovery
0.00%
IR After 8 Min Recovery
0.00%
IR After 10 Min Recovery
0.00%

The AOC CU34G2X has no signs of temporary image retention after displaying a high-contrast static image, but this can vary between units.

8.6
Picture Quality
Gradient
Color Depth
10 Bit

The AOC CU34G2X 34 has excellent gradient handling, but it's worse than most 10-bit panels. There's clear banding in darker shades, especially with gray.

10
Picture Quality
Color Bleed
Pixel Row Error
0.004%
Pixel Column Error
0.004%

There are no visible signs of color bleed on the AOC CU34G2X 34.

7.1
Picture Quality
Reflections
Screen Finish
Matte
Total Reflections
6.1%
Indirect Reflections
3.4%
Calculated Direct Reflections
2.7%

The AOC CU34G2X 34 has decent reflection handling. It performs well in a room with a couple of lights around, but the glare from strong light sources can get distracting.

7.5
Picture Quality
Text Clarity
Sub-Pixel Layout
RGB

The text clarity is good. Enabling Windows ClearType (top photo) helps improve clarity on diagonal lines, but can make straight lines less bold.

Motion
8.0
Motion
Response Time @ Max Refresh Rate
Best Overdrive Setting
Medium
Rise / Fall Time
7.0 ms
Total Response Time
13.8 ms
Overshoot Error
0.3%
Dark Rise / Fall Time
10.2 ms
Dark Total Response Time
18.6 ms
Dark Overshoot Error
0.0%

Overdrive SettingResponse Time ChartResponse Time TablesMotion Blur Photo
WeakChartTablePhoto
MediumChartTablePhoto
StrongChartTablePhoto

The AOC CU34G2X has a great response time at its max refresh rate of 144Hz. Like most VA panel monitors, there's noticeable black smear due to the slower response time in darker transitions. We recommend using the 'Medium' Overdrive setting because it's quicker than 'Weak' and has a lot less overshoot than 'Strong'. If the black smear bothers you, the 'Strong' setting has a much quicker response time, so there's no black smear, but there's inverse ghosting due to the overshoot.

7.1
Motion
Response Time @ 60Hz
Best Overdrive Setting
Medium
Rise / Fall Time
8.9 ms
Total Response Time
19.3 ms
Overshoot Error
0.9%
Dark Rise / Fall Time
9.4 ms
Dark Total Response Time
17.0 ms
Dark Overshoot Error
0.0%

Overdrive SettingResponse Time ChartResponse Time TablesMotion Blur Photo
WeakChartTablePhoto
MediumChartTablePhoto
StrongChartTablePhoto

The response time at 60Hz is okay. Once again, there's smearing due to the slow response time in darker transitions. Like at its max refresh rate, we recommend using the 'Medium' Overdrive setting, so you won't need to change the setting if the frame rate of your game drops. The 'Strong' setting has way too much overshoot.

10
Motion
Image Flicker
Flicker-Free Yes
PWM Dimming Frequency
0 Hz

The AOC CU34G2X has a flicker-free backlight at all backlight levels, which helps reduce eye strain.

7.0
Motion
Black Frame Insertion (BFI)
Black Frame Insertion (BFI)
Yes
BFI Maximum Frequency
144 Hz
BFI Minimum Frequency
100 Hz

The AOC CU34G2X 34 has a black frame insertion feature to try to reduce persistence blur. However, it works within a narrow range, and you can't use it at the same time as VRR. Also, it creates noticeable image duplication. Keep in mind that the BFI scored is based on the flicker range and not the actual performance.

9.0
Motion
Refresh Rate
Native
144 Hz
Max Refresh Rate
144 Hz
Variable Refresh Rate
Yes
FreeSync
Compatible (Tested)
G-SYNC
Compatible (Tested)
VRR Maximum
144 Hz
VRR Minimum
< 20 Hz
VRR Supported Connectors DisplayPort, HDMI

Although the AOC CU34G2X isn't officially certified by either FreeSync or G-SYNC, we confirmed it's compatible with both VRR technologies. Both work at the full range over a DisplayPort connection, while only FreeSync works over HDMI up to 100Hz.

Inputs
9.5
Inputs
Input Lag
Native Resolution
4.7 ms
Native Resolution @ 60Hz
8.7 ms
Variable Refresh Rate
4.9 ms
Variable Refresh Rate @ 60Hz
9.7 ms
10 Bit HDR
N/A
Black Frame Insertion (BFI)
7.4 ms

The AOC CU34G2X 34 has extremely low input lag that doesn't significantly increase with VRR enabled. We didn't measure the 10-bit HDR input lag because the max refresh rate with a 10-bit signal is 60Hz over HDMI, and we don't have the tools necessary to measure HDR input lag over a DisplayPort connection.

8.7
Inputs
Resolution And Size
Native Resolution 3440 x 1440
Aspect Ratio 21:9
Megapixels 5.0 MP
Pixel Density
110 PPI
Screen Diagonal 34.0"
Screen Area 412 in²

The large 34 inch screen allows you to open multiple windows side-by-side without them being too cramped together.

Inputs
Inputs
Inputs
Total Inputs
DisplayPort 2 (DP 1.4)
Mini DisplayPort No
HDMI 2 (HDMI 2.0)
DVI No
VGA No
DisplayPort Out No
USB 4 (USB 3.0)
USB C No
Analog Audio Out 3.5mm 1
Microphone In 3.5mm No
Digital Optical Audio Out No
Analog Audio Out RCA No
Power Supply Internal

You can use the USB-B upstream port to connect your peripherals to the USB ports on the AOC CU34G2X.

Features
Features
Additional Features
RGB Illumination
No
Speakers
No
HDR10 Yes
Multiple Input Display
PIP + PBP

The AOC CU34G2X has a few extra features, including:

  • LowBlue Mode: Removes blue light to help reduce eye strain.
  • Crosshair: Adds a virtual crosshair on the screen for FPS gaming.
  • Shadow Control: Adjusts the gamma to make it easier to see opponents in shadows.

Features
On-Screen Display (OSD)
Features
Controls

There are five buttons below the right side of the monitor to control the on-screen display. However, they're hard to press.

Features
In The Box

  • Power cable
  • HDMI cable
  • DisplayPort cable
  • USB-A to USB-B cable
  • User guides

Differences Between Sizes And Variants

We tested the AOC CU34G2X 34", which is the only size available for this monitor. There's also the CU34G2, which seems to only be available in Europe, though we don't know for sure.

Model Size Resolution Refresh Rate VRR
CU34G2 34" 3440x1440 100Hz FreeSync
CU34G2X 34" 3440x1440 144Hz Adaptive Sync

If you have one that performs differently from ours, let us know, and we'll update the review. Keep in mind that some tests, like gray uniformity, can vary between units.

You can see the label for our unit here.

Compared To Other Monitors

The AOC CU34G2X is a great gaming monitor that's versatile for other uses too. It's a low-cost option that offers good value, but unless you work in a dark environment, other affordable options get brighter, like the Gigabyte G34WQC

See our recommendations for the best gaming monitors, the best ultrawide monitors, and the best budget monitors.

Gigabyte G34WQC

The AOC CU34G2X and the Gigabyte G34WQC are both great gaming monitors. They have similar features with the same panel type and max refresh rate. Even though the Gigabyte is certified by AMD to have native FreeSync support, FreeSync still works on the AOC, and G-SYNC works on both. The Gigabyte has a quicker response time, but black smear is visible on both. The Gigabyte is better to use in a well-lit room because it has better reflection handling and gets brighter. However, the AOC has four USB inputs, which the Gigabyte doesn't have, and its stand offers swivel adjustments.

LG 34GN850-B

The LG 34GN850-B and the AOC CU34G2X are both great gaming monitors with different panel types. The LG has an IPS panel with wider viewing angles, while the AOC has a VA panel with higher contrast. Motion looks much better on the LG because it has a quicker response time, and it doesn't have black smearing like on the AOC. The LG also gets much brighter, so it does a better job at fighting glare. If ergonomics are important to you, the AOC offers swivel adjustments, which the LG doesn't.

Gigabyte M27Q

The Gigabyte M27Q and the AOC CU34G2X are very different monitors. The Gigabyte is a 27 inch monitor with a 16:9 aspect ratio, while the AOC is bigger at 34 inches and has a 21:9 aspect ratio for more screen space. They also have different panel types with unique characteristics; the Gigabyte has an IPS panel with wider viewing angles, and the AOC's VA panel has a higher contrast ratio. They each have a high refresh rate and VRR support for gaming, but motion looks smoother on the Gigabyte due to the quicker response time.

ASUS TUF Gaming VG34VQL1B

The ASUS TUF Gaming VG34VQL1B is a bit better gaming monitor than the AOC CU34G2X. The ASUS has significantly faster response times, but there's noticeable black smear on either due to their VA panels. The ASUS has a 165Hz panel compared to 144Hz on the AOC, and while the ASUS is certified by AMD, FreeSync and G-SYNC work on both. The ASUS also gets significantly brighter and has better reflection handling, so it's a better choice for well-lit rooms. However, the AOC has better ergonomics because it has a much wider swivel and tilt range.

Samsung Odyssey G5 LC34G55T

The Samsung Odyssey G5 LC34G55T and the AOC CU34G2X are both great gaming monitors. The Samsung has a higher 165Hz refresh rate compared to 144Hz on the AOC, and while the Samsung has native FreeSync support, which the AOC doesn't have, FreeSync still works on it. The Samsung is a bit better to use in a well-lit room because it has better reflection handling and gets a bit brighter. It also has a much higher contrast, but this can vary between units. On the other side, the AOC has many more ergonomics adjustments, as you can swivel it and adjust the height, which you can't do on the Samsung.

Acer Nitro XV340CK Pbmiipphzx

The Acer Nitro XV340CK Pbmiipphzx and the AOC CU34G2X are both great ultrawide gaming monitors. They have different panels with pros and cons. While the Acer has an IPS panel with wide viewing angles and low contrast, the AOC has a VA panel with high contrast and narrow viewing angles. They each have a 144Hz refresh rate, but the Acer has native FreeSync support, and the AOC is FreeSync compatible. Motion looks smoother on the Acer because it has a quicker response time, too.

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