Review unit on loan from Asus Singapore

The ASUS Zenbook Duo UX8406 is the new model released in 2024 for the Zenbook Duo series. As the name suggests, there are two displays, and this time there are two full-sized displays compared to the half-height ones from the previous models. This laptop has two 14-inch 16:10 touchscreen 120Hz OLED displays. Weight is advertised as 1.65kg.

Here in Singapore you get the Intel Core Ultra 9 (16-core), 16GB RAM and 1TB SSD for SGD 2999 (or USD 1499). Increase the RAM to 32GB and price goes up to SGD 3399.

My review is from the perspective of a visual content creator. This review will cover how useful dual stacked displays is with workflow for graphic design, photography and video editing.

Bottom line

If your workflow or productivity can benefit with the use of two displays, this laptop is worth considering. The design looks good and is practical and functional. Overall performance is lag-free for graphic design work and photography. For editing 4K videos, the system will be sluggish when importing video clips and generating thumbnails.

When it comes to productivity, you just can't beat dual display productivity with just one display. ASUS has also added several useful software features to go with the dual display workflow.

For graphic design work, I would prefer a big display, but that really depends on the software you use.

While the display has pen support, the pen performance is good enough for writing and casual drawing, certainly not good enough for creating professional illustration.

Specifications

• OS: Windows 11 Home
• Processor: Intel® Core™ Ultra 9 Processor 185H 2.3 GHz (24MB Cache, up to 5.1 GHz, 16 cores, 22 Threads); Intel® AI Boost NPU
• Graphics: Intel Arc Graphics
• Neural processor: Intel AI Boost NPU
• Display: 14-inch, 2880 x 1800, 16:10 OLED @ 120Hz
• Brightness: 400 nits standard, 500 nits HDR
• Colour support: 100% DCI-P3, 1.07 billion colours
• Contrast ratio: 1 million to 1
• Memory: 16GB, 32GB
• Storage: 1TB M.2 NVMe PCIe 4 SSD
• Ports: USB type A 3.2, 2x USB type C Thunderbolt 4, HDMI 2.1, 3.5mm audio jack
• Audio: Harman Kardon speakers
• Network: WiFi 6E, Bluetooth 5.3
• Battery 75 Whrs
• Power supply: 65W USB-C adapter
• Weight: 1.65kg (1.35kg system + 0.30kg keyboard)
• Dimensions: 31.35 x 21.79 x 1.46-1.99cm
• Included in the box: Backpack, Sleeve, ASUS Pen SA203H with MPP 2 support)

Things included

In the box is a 65W USB-C adapter, power cable, ASUS Pen 2 (SA203H) and the laptop. Here in Singapore there's also a laptop bag included, but that may not be included in other countries.

Design

Design of the laptop looks beautiful, functional and versatile. The laptop can be deployed in several modes. There's the usual laptop mode, the top-bottom dual display mode and the side by side display mode. You can choose which mode works best for you.

Biometric security with Windows Hello face unlock is effective and fast.

The display lid is matte textured and is quite resistant to fingerprints, and there's a subtle ASUS logo.

The various deployment modes are possible thanks to the built-in kickstand underneath the laptop. The kickstand is made of metal and hinge is strong. There are rubber contact feet at all the right places to keep the stand in stable position.

Speakers use Harmon Kardon tech which is good. Audio is loud but they face away and hence will not sound perfect.

Overall build quality is solid. This is a well made laptop.

User upgradability is possible for the single SSD but it is difficult to get inside the back. The cover hidden behind the kickstand is actually not for the SSD slot but for some PC component. That cover has to be removed, followed by eight Torx screws before you can open the back.

Ports on the left are USB 3.2 type A and two Thunderbolt 4 USB-C. Fan exhaust grilles are on both sides. Fan noise is audible when system is under full load but not as loud as gaming laptops where you have to put on headphones for gaming for better audio experience.

Ports on the right are full-size HDMI v2.1 and 3.5mm audio jack

The wireless Bluetooth keyboard can attach securely on the bottom display with magnets. The keyboard can be removed easily by lifting from either side.

The keyboard has pogo pin connectors that connect to the laptop. When connected, the bottom display is disabled. When the keyboard is removed, the bottom display powers on automatically.

Underneath the keyboard is matte textured rubber to prevent scratches on the display. The keyboard will lay flat on the table. I recommend cleaning the bottom occasionally just to remove any physical dirt to prevent anything from getting onto the bottom display when keyboard is attached.

The typing experience is better than I expected and very similar to a laptop with a good keyboard. Key travel is 1.4mm. Keyboard is backlit.

Charging the keyboard can be done through the USB-C port by the side. I did not measure the battery life of the keyboard and I am not sure if the keyboard can be charged through the pogo pin connectors.

Even if the keyboard runs out of battery, you can fall back on using the virtual keyboard. You can choose between full and half-height keyboard layouts. Typing experience is not ideal since there are no physical keys.

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The quality of the two OLED displays is identical. Each display is a 14-inch OLED display with 2880 x 1800 resolution and 120 Hz refresh rate. HDR brightness is rated at 500 nits.

I measured colour support for 100% sRGB, 100% P3, 92% AdobeRGB, 90% NTSC and brightness of 341 nits with a Spyder X2 calibrator.

The displays are bright enough for use in bright room environment. Colours are vibrant and viewing angles are good. These displays are reasonably colour accurate and hence suitable for visual content work.

Only downside is the displays are really reflective. It would have been great if ASUS could use some sort of anti-reflective coating.

ASUS has added custom software to handle the layout and placement of windows and apps across both displays. When you drag any window by the title bar, a popup will appear to let you decide where to place that window, on which display and in which area. This software makes dual display workflow even more productive.

Performance

This review unit is using the Intel Core Ultra 9 Processor 185H @ 2.3 GHz (24MB Cache, up to 5.1 GHz, 16 cores, 22 Threads). I read online there's another model with Intel Core Ultra 7 155H @ 1.4Ghz. These are both 16-core processor and they are powerful.

The only time when I experience lag or sluggishness is when importing 4K videos and while waiting for thumbnails to generate in Davinci Resolve for video editing. After the videos are imported and thumbnails generated, video editing process is smooth. The laptop is definitely more than powerful enough to handle graphic design and photo editing.

This is not a gaming laptop but light gaming is possible with the Intel ARC graphics. Don't expect to play graphics intensive games at high frame rates though.

Dual display workflow

For graphic design, having one larger display is probably better than two displays since most graphic design apps don't really support dual displays.

But having two displays means the other display can be used to show reference, or have some other apps open.

There's dual display feature for Adobe Lightroom but it doesn't seem that useful depending on the mode you're in. It's useful in grid mode where you can cycle through thumbnails and the photo can show up big on the other display.

When editing photos, you see the same photo on both display and the sizes are not drastically different.

Davinci Resolve has dual display feature that allows you to spread the tools across both displays.

I find vertical deployment to be more useful when viewing vertical content, such as when writing or browsing webpage. This will be great for programming too. The 16:10 aspect ratio displays means vertical mode will not look too narrow when in portrait orientation. There is auto-rotate when the displays are rotated.

Drawing performance

ASUS Pen 2 (SA203H) supports MPP 2, palm rejection, tilt and 4096 levels of pressure sensitivity. Pen tip is firm and has minimal movement. No replacement pen tips are included unfortunately.

Touchscreen works well for basic navigation gestures such as pan, zoom and rotate.

Display is laminated so there's almost no gap between the line and the pen tip. There is parallax and no cursor misalignment. Cursor is always directly beneath the pen tip even at the extreme edges of the display.

The hard plastic pen tip glides quite smoothly on the glass so it will take some time to get used to for drawing.

These are line tests created with Medibang Paint Pro. Note ASUS does not have software to customise the pen pressure. If you need pen pressure customisation, that will have to come from the drawing app you use.

1. Initial activation force is low but not minimal. It is not easy to maintain consistent line width when drawing with minimal pressure.

2. To draw thin lines more easily, I have reduced the brush size so that I can draw with more pressure. There is slight diagonal line wobble or jitter.

3. Lines are not able to taper smoothly and sharply.

4. Line transition from thin to thick looks alright. This is also a diagonal line and there is diagonal line wobble or jitter.

5. I'm trying to maintain consistent line width by maintaining consistent pressure. There's some variance with the width/thickness. If you want really smooth lines, you will have to draw faster.

6. Dots have to be draw by tap and drag with this app. Other apps have no such problem.

7. The pen is not great at detecting minimal changes in pressure when drawing with minimal pressure. This means when you have a thick brush, it's difficult to draw thin lines. And as such, line work has a tendency to have the same width unless you reduce the brush size by number and not by pressure. So to draw thin lines, you have to reduce the brush size manually, and to draw thick again, you increase brush size. It's certainly not as convenient compared to using a pen that's really sensitive.

In reality, 4096 levels of pressure is a lot, but this pen is not good at drawing with minimal pressure.

The pen has problems with diagonal line wobble and line tapers, and those obviously affect accuracy, and hence the drawing performance is definitely not good enough for creating professional illustrations.

Here's a quick sketch drawn with Medibang Paint. I had a reference in the top display, and drew on the bottom display and it was really convenient to have an extra screen for reference.

Drawing experience is not the best. The pen glides a bit too easily (slippery) on the glass surface so that will affect control. And then there's the issue with the initial activation force and line wobble. So it was not easy for me to draw straight lines.

For writing, it works great.

Writing and drawing is best done on the bottom display since that's resting on the table or stand and will not wobble. When you're just using the bottom display, there's no way to power off the top display. ASUS software only allows powering off the bottom display and not the top.

Battery life

Battery capacity is 75 Whr. Battery life will vary significantly depending on how many displays are used, brightness and what you're doing.

Battery life for a single display is around 8 to 10 hours. Battery life for two displays is 4 to 5 hours and on the lower side. If you're doing work where the fans rev up, battery life will be lower. E.g. Editing photos or videos.

When using dual displays, it's best to just connect the laptop to power.

Conclusion

As mentioned eariler, dual display productivity is amazing. However whether you can benefit from having a dual display really depends on the apps you use. The selling point here is you get dual display portability. If you don't mind having just one display, you can always connect to an external display at home or in the office. Another advantage is this dual display setup does not take up much space on the table.

The only downsides for this laptop would be the back-facing speakers and it's cannot handle graphics intensive games.

Design of the ASUS Zenbook Duo UX8406 is beautiful and versatile. Build quality is good, better than expected.

Pros and cons at a glance
+ Compact, portable, lightweight
+ Decent build quality
+ Bright, vibrant OLED displays
+ Adaptive brightness
+ Dual display is great for productivity
+ ASUS and included useful dual display software
+ Wireless keyboard is convenient
+ Typing experience of the keyboard is good
+ Display feels more solid than the ASUS Zenbook Fold 17 OLED (UX9702) from 2023
+ Design with dual displays and keyboard is versatile
+ Decent selection of ports
- Pen glides too easily is good for writing, not for drawing
- No way to disable top display and use only the bottom display
- No driver to customise pen pressure globally
- Pen has issues with initial activation force and diagonal line wobble
- Speakers are loud by lack bass
- Speakers face back when both displays are standing
- Battery life for dual display is around 4-5 hours.

Availability

You can find the ASUS Zenbook Duo UX8406 on Amazon (US | CA)

If you're from Singapore, you can find the laptop on Shopee SG and Lazada SG