Asus Zenbook Duo (UX8406) Review

Asus has tinkered with dual-screen laptops for half a decade, but 2019’s Zenbook Pro Duo and 2021’s Zenbook Duo 14 merely put a smaller second display between the main screen and keyboard. This year’s Asus Zenbook Duo ($1,499.99 as tested) commits to the bit: It’s a 14-inch OLED laptop with another 14-inch OLED panel where you expect the keyboard to be, letting you either use the second screen as a touch-screen keyboard, enjoy dual-monitor productivity with the included detached Bluetooth keyboard, or attach the keyboard to the secondary display for that traditional laptop experience. Basically, it’s a slightly larger alternative to 2023’s innovative Lenovo Yoga Book 9i, but its lower price makes it an even more deserving Editors’ Choice award winner for dual-screen laptops.

Configurations: Two CPUs, Two Resolutions 

Our CES preview of the Zenbook Duo focused on the deluxe UX8406MA-PS99T model, which has twin 2,880-by-1,800-pixel OLED touch screens, Intel’s new Core Ultra 9 185H processor, 32GB of RAM, and a 1TB solid-state drive. Its $1,699.99 price undercuts the 13.3-inch Yoga Book 9i—with similar displays, a Core i7-1355U chip, and half the memory and storage—by $300.

(Credit: Eric Grevstad)

Today’s review unit, model UX8406MA-DS76T, is $1,499.99 with a milder Core Ultra 7 155H CPU, 16GB of RAM, and two OLED touch panels with 1,920-by-1,200-pixel resolution. Both Duos come with Windows 11 Home, a stylus pen with USB-C charging, and the flat keyboard that fits between the screens with the laptop shut and is held magnetically when covering the lower (upward-facing) display.

(Credit: Joseph Maldonado)

The Zenbook Duo opens to lie flat (what the company calls sharing mode for users on either side of a desk) but doesn’t open past 180 degrees as the Yoga Book does. So, you can’t fold the screens back-to-back and carry it as a tablet. Like the Lenovo, however, it provides a choice of laptop mode—presumably usually with the detachable keyboard in place—or dual-screen desktop use in either side-by-side vertical (portrait) or stacked horizontal (landscape) orientation. For the portrait position, you open it and stand it on end. For the landscape position, a built-in rear kickstand props up the lower screen, which is more convenient than the Yoga’s separate origami stand. 

(Credit: Joseph Maldonado)

Either way, you’ll notice a bar between the screens (like the adjacent bezels in a dual-monitor desktop setup), but Asus brags that it gives you a 19.8-inch workspace instead of a single 14-inch display, and it’s far handier than carrying both a laptop and a USB portable monitor. The Duo has passed MIL-STD 810H tests for road hazards like shock, vibration, and high and low temperatures; it feels sturdy with no flex when you grasp the screen corners. 

(Credit: Joseph Maldonado)

Clad in what the company calls Inkwell Gray aluminum, the Zenbook Duo measures 0.78 by 12.3 by 8.6 inches while exceeding our ultraportable weight limit at 3.64 pounds—the hinged screens qualify at 2.98 pounds but the keyboard adds 11 ounces. The Yoga Book 9i is more compact at 0.63 by 11.8 by 8 inches, but the Duo isn’t much bulkier than the single-screen Asus Zenbook 14 OLED (0.59 by 12.3 by 8.7 inches; 2.82 pounds).

(Credit: Joseph Maldonado)

While you’ll find two USB-C Thunderbolt 4 ports (suitable for the power plug) on its left edge, the Asus doesn’t limit its ports to them as the Lenovo does. You’ll also find a USB 3.2 Type-A port on the left and an audio jack and HDMI monitor port on the right. Meanwhile, Wi-Fi 6E and Bluetooth handle wireless connections.

(Credit: Joseph Maldonado)

Using the Asus Zenbook Duo: Let Your Fingers Do the Walking

With the Duo in laptop mode, remove the Bluetooth keyboard and the lower screen comes on…albeit with an annoying “HDR-ready display detected” pop-up every time. Tap it with six fingers to summon a virtual keyboard, which can occupy either the lower half of the display (with or without a small touchpad area at right) or all of it (with the touchpad below). Icons above the virtual keyboard let you choose its language, type emojis, or toggle a row of function-key shortcuts above. Tap with three fingers to summon a two-button virtual touchpad in that spot.

Start dragging an application window, and a pop-up lets you assign it to screen 1, screen 2, or fill both. (This last option is also available with a five-finger zoom gesture.) Tap or click the ScreenXpert icon at the bottom left of screen 1, and an icon menu lets you toggle the virtual keyboard, check the Bluetooth keyboard’s battery, disable screen 2, toggle screen rotation or the microphone, and choose different or mirrored displays for sharing mode (the system opened flat with screen tops at the hinge). You can also activate a virtual numeric keypad, a handwriting area, or a control panel for brightness, volume, and other settings with a six-finger downward swipe.

(Credit: Eric Grevstad)

Unless you’d rather have one-and-a-half screens than either one or two, you’ll presumably opt for the Bluetooth keyboard rather than use the virtual on-screen one. Like on its tablet siblings, the touch-screen keyboard is useless; you can turn off its loud, annoying click, but you can’t do anything about its total lack of typing feel, accidental skipping and tripling of keystrokes, and unwanted Caps Lock. I managed to type a few sentences by slowing to a hunt-and-peck crawl and tapping with meticulous precision—and the virtual touchpad worked fine.

However, the physical keyboard is infinitely more comfortable, despite devoting its lower half to a too-big palm rest with a buttonless touchpad. Adding to its usefulness, this Bluetooth keyboard connects to the device using pogo pins that also allow the laptop to charge it while connected.

(Credit: Joseph Maldonado)

The keyboard has a Bluetooth on/off switch and a USB-C port for charging via cable when not resting over the lower screen. (Mind you, the cable provided for charging the pen is too short.) It has a switchable backlight—which drains its battery quickly—and a flat but reasonable typing feel. The 6.5-inch pen has two buttons and 4,096 levels of pressure sensitivity; it kept up with my swoops and scribbles with decent palm rejection in a brief test. 

(Credit: Joseph Maldonado)

The 1080p webcam supports Windows’ newish auto-framing and background-blur effects. It captures fairly well-lit and colorful (if slightly pale) images with minimal static. Sound from the bottom-mounted speakers is surprisingly loud, but it can be rough and harsh at high volume. With the level turned down to 60% or less, vocals and instrumentals are clear, albeit short on bass, and it’s possible to make out overlapping tracks. 

(Credit: Joseph Maldonado)

What’s the only thing better than an ultra-high-contrast OLED laptop screen? Two of them. Both of our Zenbook Duo’s 1,920-by-1,200-pixel panels are crisp and colorful, with wide viewing angles and fine details. Hues are richly vivid and saturated, with inky blacks and pristine white backgrounds. More brightness would have been ideal, but the Zenbook Duo is plenty bright enough for office settings.

(Credit: Joseph Maldonado)

The included MyAsus control software includes Dolby Atmos dynamic, music, movie, game, voice, and equalizer presets as well as system updates, microphone adjustments, and screen settings. Those screen settings include Tru2Life video enhancement and vivid, sRGB, and DCI-P3 color palettes.

Testing the Asus Zenbook Duo: It’s a Core Ultra World 

The Zenbook Duo’s 13.3-inch competitor (inspiration?) the Lenovo Yoga Book 9i is an obvious choice for our benchmark comparisons. Another is the latest HP Spectre x360 14, a 2-in-1 convertible with the same Core Ultra 7 CPU as the Duo. So do the two conventional clamshells that round out our charts: Asus’ Zenbook 14 OLED UX3405 and the thrifty Acer Swift Go 14.

Productivity Tests 

We run the same general productivity benchmarks across both mobile and desktop systems. Our first test is UL’s PCMark 10, which simulates a variety of real-world productivity and office workflows to measure overall system performance and also includes a storage subtest for the primary drive. 

Three other benchmarks focus on the CPU, using all available cores and threads, to rate a PC’s suitability for processor-intensive workloads. Maxon’s Cinebench R23 uses that company’s Cinema 4D engine to render a complex scene, while Geekbench 5.5 Pro from Primate Labs simulates popular apps ranging from PDF rendering and speech recognition to machine learning. We also use the open-source video transcoder HandBrake 1.4 to convert a 12-minute video clip from 4K to 1080p resolution (lower times are better). 

Finally, we run PugetBench for Photoshop by workstation maker Puget Systems, which uses the Creative Cloud version 22 of Adobe’s famous image editor to rate a PC’s performance for content creation and multimedia applications. It’s an automated extension that executes a variety of general and GPU-accelerated Photoshop tasks ranging from opening, rotating, resizing, and saving an image to applying masks, gradient fills, and filters.

The Zenbook Duo finished at or near the front of most tests, showing plenty of pep for everyday office apps and modest multimedia creation. One minor alarm bell is that it struggled to clear 500 points in my first run of PugetBench for Photoshop, which came after a couple of hours of other benchmarks (on AC power with both Windows’ and MyAsus’ power modes set for best performance). When I reran the test the next day, the Duo did much better, indicating it runs warm and throttles down after strenuous exercise to avoid overheating.

Graphics Tests 

We test Windows PCs’ graphics with two DirectX 12 gaming simulations from UL’s 3DMark, Night Raid (more modest, suitable for laptops with integrated graphics) and Time Spy (more demanding, suitable for gaming rigs with discrete GPUs). We usually add two tests from the cross-platform GPU benchmark GFXBench 5, which stresses both low-level routines like texturing and high-level, game-like image rendering, but the Duo failed to launch that program.

The Asus hybrid kept pace with its peers, but none of these lightweights’ integrated graphics comes within a country mile of the discrete GPU of a gaming laptop. Casual gaming and video streaming, not fast-twitch titles, are their after-hours pastimes. 

Battery and Display Tests 

We test each laptop’s battery life by playing a locally stored 720p video file (the open-source Blender movie Tears of Steel) with display brightness at 50% and audio volume at 100%. We make sure the battery is fully charged before the test, with Wi-Fi and keyboard backlighting turned off. 

We also use a Datacolor SpyderX Elite monitor calibration sensor and its Windows software to measure a laptop screen’s color saturation—what percentage of the sRGB, Adobe RGB, and DCI-P3 color gamuts or palettes the display can show—and its 50% and peak brightness in nits (candelas per square meter).

The Zenbook Duo predictably lasted longer with one display active—the other covered by the Bluetooth keyboard—than with two. (The Yoga Book 9i insisted on lighting both screens during our test.) Its battery life trailed the Spectre’s and the Zenbook 14’s but proved more than sufficient, and it joined the other OLED laptops in driving unbeatable color coverage with decent, if not brilliant, brightness.

Verdict: Two Screens, Few Compromises 

The 2024 Asus Zenbook Duo is a first-class alternative to the Lenovo Yoga Book 9i that last year inspired us to predict the long-term demise of portable monitors as laptop accessories. It has more ports, a lower price, and a newer CPU with Intel’s AI enhancements. 

(Credit: Joseph Maldonado)

No, the tablet-cover-style Bluetooth keyboard doesn’t feel as snappy as an actual laptop keyboard, but it’s not much of a trade-off for the added versatility and working area of dual displays. The Duo decisively wins Editors’ Choice honors for dual-screen laptops. If you’re focused on maximizing productivity while commuting or traveling for work—and enjoying a high-end mobile movie player when it’s time to log off—then definitely consider the Asus Zenbook Duo.