Asus Zenbook Duo (2024, UX8406) review: A great laptop for work, rest or play

The Asus Zenbook Duo is a 2-in-1 laptop tour de force. Having had my twin-screen appetite whetted by the brilliant – but flawed – HP Spectre Fold 17 last month, the Zenbook Duo is a vastly more practical alternative.

Instead of a single folding OLED screen, the Duo has separate twin 14in screens, connected by a regular laptop hinge. You can run it as a single screen notebook or a dual-screen desktop powerhouse. It’s a lot cheaper than the HP, more powerful and comes with more up to date internals. Critically, it feels less experimental and more like a laptop you’d be able to rely on to get things done quickly.

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Asus Zenbook Duo (2024, UX8406) review: What you need to know

I saw the Asus Zenbook Duo first at CES 2024 in Las Vegas and I was impressed. Its key appeal is its pair of twin 14in screens. Each of these is an OLED panel with adaptive 120Hz refresh and each has a native resolution of 2,880 x 1,800. Unfolded, they deliver an absolutely huge amount of screen real estate compared with a regular laptop and at not too much of a weight and bulk penalty.

The Zenbook Duo weighs 1.7kg with its Bluetooth keyboard attached and it is 24.5mm thick. Its footprint is pretty much the same as the svelte Asus Zenbook 14 OLED.

As with other dual-screen/folding laptops we’ve seen in recent times, the Zenbook Duo can be used as a regular laptop, with a Bluetooth keyboard attached and obscuring the lower display, or unfolded on a desktop with both displays enabled. A sturdy built-in kickstand below the base between a set of rubber feet means it’s always ready to be used in this mode and this kickstand works in both portrait and landscape mode.

Inside, the Zenbook Duo is equipped with the latest Intel Silicon – either an Intel Core Ultra 9 185H CPU or Core Ultra 7 155H with Intel Arc graphics. It also comes with either 16GB or 32GB of RAM and either a 1TB or a 2TB SSD. There’s a pressure-sensitive stylus included in the box, too, along with that detachable Bluetooth keyboard.

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Asus Zenbook Duo (2024, UX8406) review: Price and competition

Configuration tested: Intel Core Ultra 9 185H CPU with Arc Graphics; 32GB RAM; 2TB SSD; 2x 14in 120Hz OLED display; Price: £2,000

The price for the Asus Zenbook Duo I have here for testing is a refreshingly reasonable £2,000, and that gets you the one with a top-end Intel Core Ultra 9 185 CPU inside, accompanied by 32GB of RAM and a bigger 2TB. There will also be a lower-powered and (presumably) cheaper Core 7 Ultra model available, eventually, though so you might want to wait for that to arrive.

At these sorts of prices, the Zenbook Duo comes up against numerous single-screen competitors, but none that offer quite the same expanse of screen real estate or ergonomic choices this laptop does.

Its closest competitor is the Lenovo Yoga Book 9i – another dual-screen machine, but one with smaller 13.3in displays and whose keyboard lacks a touchpad. We prefer the Yoga Book’s 360-degree hinge because it lets you use the laptop in more modes than the Zenbook Duo’s. However, prices for the latest model are somewhat higher than the Zenbook Duo, starting at £2,405 for the Core i7 Ultra model with 16GB of RAM and a 512GB SSD.

The HP Spectre 17 Fold is even more impressive. It’s a 12in laptop that unfolds to give you a single 17in screen without any kind of dividing line between screens, like a giant folding phone – but it’s ludicrously expensive at £4,999.

In the meantime, if it’s just a big screen you’re after, then it might be worth considering the LG Gram 17, a laptop with a 17in screen that weighs more like a 14in laptop. It doesn’t have a touchscreen, though, and it is a little on the large side despite its light weight.

Our favourite lightweight big-screened laptop, however, has to be the M2 Apple MacBook Air 15in. It delivers the best compromise between screen size, performance and size of any laptop we’ve ever tested, and it combines that with incredibly long battery life.

It lacks a touchscreen, however, and its single display, while 15in across the diagonal can’t compete with the Zenbook Duo’s huge expanse of screen space. You’ll also be paying the same for an M2 MacBook Air 15in with 16GB of RAM and a 1TB SSD as the Asus Zenbook Duo.

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Asus Zenbook Duo (2024, UX8406) review: Design and key features

One thing to get out of the way before I start on anything else: the Asus Zenbook Duo is no gimmick. I’ve used it in desktop mode to do all the research and the writing of this review and I would absolutely love to switch to it for all my work. Let me explain why.

With the Zenbook Duo, I would only need one machine for working both at home and on the move. There would be no need to keep a bulky external monitor on my desk because it has a second display built in for extra productivity and it’s compact and light enough to sling in a bag to take on a work trip or holiday. Even battery life isn’t bad, although as we’ll see later, it’s still no match for a MacBook Air or Pro.

From its head to its toes, the Zenbook Duo is a confidently constructed machine with few compromises. The hinge is smooth and robust, the keyboard is a dream to type on with plenty of comfy travel, and there are plenty of ports and sockets scattered around the edges.

There’s a USB-A 3.2 port on the left, alongside twin Thunderbolt 4 ports supporting display and power delivery; and there’s a full-size HDMI port on the right edge, next to a 3.5mm headset jack. The only disappointment is that Asus hasn’t found room for an SD card slot. Practically speaking, though, the rest of this machine is pretty much beyond reproach.

In laptop mode, the system’s detachable Bluetooth keyboard completely covers the lower screen and, cleverly, charges and talks to the laptop via a set of six pogo-pin connectors at the lower edge. Not only does this ensure you can always use the keyboard, no matter the status of the battery within, but also that the laptop doesn’t have to waste power connecting to the keyboard via Bluetooth and keep it topped up with power. It also means you can continue to use the laptop while it’s in flight mode, without having to sneakily re-enable Bluetooth.

It’s a great laptop in this mode, but the Zenbook Duo’s party trick comes when you remove the keyboard from its magnetic moorings, fold out the sturdy metal kickstand on the underside of the base, and prop up the laptop on your desk. With two 14in displays, one above the other, you can have your working document on the upper screen and a browser for research on the lower screen; a Photoshop instance on one and your website CMS on the other – the possibilities are endless.

It’s even possible to set up the Duo in portrait mode, although this doesn’t work quite as well, because you can’t adjust the angle of the screens, and one of the displays always faces slightly away from you because the screens don’t align perfectly end-to-end – one is always slightly stepped behind the other, due to the way the hinge is configured.

In fact, you can discard the Bluetooth keyboard altogether, if you want to reduce the weight of the thing and use it like a giant, twin-screen tablet, typing using Asus’ touchscreen when necessary. This isn’t a working mode I’d recommend, though, because the keyboard is a bit of a horror to use: it’s laggy and the reflectivity of the display means any lights set into the ceiling will gleam distractingly on the surface of the onscreen keyboard.

What works better, are the small handful of proprietary tweaks Asus has made to ensure you can make the most of those two displays. The first of these is a pop-up window that allows you to quickly assign any window to the upper or lower screen, or maximise it across both.

There are a couple of special function keys, one for swapping the contents of screen 1 with what’s on screen 2 – great if you’re working on a document and spreadsheet simultaneously and are continually switching between the two; the other for toggling the second screen on and off, another useful tool. Although it would be if it worked consistently.

I found it worked well when I wanted to turn off the second screen, but sometimes failed to turn it back on. Attaching and removing the keyboard seemed to fix the problem but ideally, this is something Asus should fix in a future firmware update.

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Asus Zenbook Duo (2024, UX8406) review: Displays

Still that small irritation fades into insignificance next to Zenbook’s wondrous pair of 14in OLED displays, both built to the same specification to ensure you get exactly the same viewing experience on both.

If you purchase the cheaper Core 7 Ultra model, you get 60Hz, 1,920 x 1,200 resolution panels, while those who buy the Core 9 Ultra get higher spec 120Hz, 3K (2,880 x 1,800) screens. Other than sharpness and refresh rate, though, they’re equivalent.

Quoted peak brightness sits at 400cd/m, rising to 500cd/m2 in HDR playback. Both displays are Pantone validated, each covers a quoted 100% of the DCI-P3 colour gamut and they are, of course, touch-capable and support the use of a pressure-sensitive stylus, one of which is included in the box.

In testing, both panels impressed. In Native mode, I measured maximum colour capacity at  117.3% of DCI-P3 on the primary display and 120.2% on the secondary. Colour accuracy, meanwhile, was equally impressive across the system’s three user-selectable display modes.

On the primary display, I recorded an average colour difference score of 0.89 in the Duo’s sRGB mode, 0.91 in Display P3 mode and 0.98 in DCI-P3 mode. The secondary display was just as impressive, with average Delta E scores of 0.97 in sRGB, 1.09 in DCI-P3 and 0.98 in Display P3.

Measured brightness in these tests, meanwhile, hovered around 390cd/m2, and I measured highs of 630cd/m2 in HDR playback on screen one and 637cd/m2  on screen two, with a 10% white patch against a black background.

What does all this mean? First, the displays are well matched. More importantly, though, it means they’re technically excellent, and suitable for a range of purposes, from watching HDR movies on Disney Plus and Netflix, to colour critical design, video editing and photographic work.

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Asus Zenbook Duo (2024, UX8406) review: Camera, microphone and audio

The Zenbook Duo’s webcam is less impressive. It’s an 1080p infrared unit that supports Windows Hello login, but quality is so so. Colours are well balanced and the image generally well exposed. The problem is noise in low-light conditions – there’s lots of it. Somewhat disappointingly, there’s also no built-in physical privacy shutter.

One supposed positive is that the new NPU (neural processing unit) on the laptop’s Core i9 Ultra CPU lets you blur the background using Windows 11’s new AI-based Studio Effects. This means it should have a lower impact on CPU activity than, say, Zoom’s native background blur and, away from the mains at least, that should lead to less of an impact on battery life.

In practice, however, I didn’t see much of a reduction in CPU activity when enabling Windows AI camera effects versus Zoom’s native effect. Maybe a 1-2% reduction in CPU usage but not much more than that. Perhaps this is something that will have more of an effect on lower powered systems but with the Zenbook Duo I’m not convinced it has a huge impact.

Elsewhere, the microphone is effective but only if you turn on the AI noise cancelling modes in the MyAsus settings software. This cuts out background noise effectively and cleans up the audio significantly, although if you listen closely, you can hear the processing “squelch”.

And the speakers are acceptable if not stellar. There’s loads of volume on tap here but when you pump up the volume it sounds harsh and there isn’t much in the way of warmth or bass. Again, you’ll find better in a MacBook Air or, indeed, one of Asus’ excellent Zenbook 14 machines.

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Asus Zenbook Duo (2024, UX8406) review: Performance

You have a choice between two CPUs when you buy an Asus Zenbook Duo: one with an Intel Core Ultra 7 155H inside or one with an Intel Core Ultra 9 185H. The latter is the model I’ve been testing for this review.

The Intel Core Ultra 9 185H is a 16-core part with support for up to 22 threads and it runs at a maximum boost frequency of 5.1GHz. As has become the norm, those cores aren’t all the same: six are performance cores and used for the heavy lifting, eight are “Efficient” cores for low-power jobs and two are dedicated to lightweight background tasks – the “Low-power Efficient” cores.

The CPU also encompasses a number of other computing “tiles” as Intel refers to them: an NPU (neural processing unit), designed to accelerate AI tasks such as the aforementioned Windows Studio Effects tools, and a new Intel Arc Graphics tile, which is a big step up on the old Iris Xe graphics.

In testing, the Asus Zenbook Duo put in a decent performance across-the-board, but it was more impressive in some areas than in others. In Geekbench 6, for instance, it was significantly faster than even the M3 MacBook Pro 14in I tested last year, and it was just as quick, relatively speaking, in the Cinebench r23 CPU tests and our in-house 4K media conversion tests. However, it also lagged behind the Huawei Matebook 16s with its Core i9-13700H chip from 2023.

For GPU-focused tasks and gaming, it’s a similarly mixed picture. In the OpenCL Compute benchmarks it’s clearly a big step up over any Intel CPU with Iris Xe onboard but the basic M3 MacBook Pro outstrips it and does so a lot more quietly as well. As soon as you put the Zenbook under any kind of stress – like most Windows machines – its fans fire up and emit a noticeable whooshing noise.

Still, the advancement over Iris Xe is quite eye-opening when you compare it with the otherwise pretty punchy Huawei Matebook 16s. In the Serious Sam 4 benchmark, run at 1080p with fairly undemanding settings selected, I saw more than double the frame rate with the Zenbook Duo.

I was worried that with all this power on tap and the power demands of those two screens, that battery life would suffer but that turned out not to be the case. In laptop mode – because probably you’d have the machine plugged into the mains in desktop mode – it lasted a creditable 10hrs 51mins in our video playback test.

There’s still only one game in town when it comes to lengthy laptop battery life, Apple’s MacBook lineup, but this isn’t disastrous by any means.

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Asus Zenbook Duo (2024, UX8406) review: Verdict

In fact, it confirms to me that Asus has a bit of a wonder on its hands with the Asus Zenbook Duo. Not only is this the best realisation I have yet come across of the dual-screen laptop concept, it’s also a usable, practical laptop, period.

It’s well-made and usable. The two screens serve a genuine purpose – you’ll be more productive and comfortable at your desk – battery life is decent and all-round performance is impressive.

Best of all, it’s not as hideously expensive as you might expect it to be, undercutting the Lenovo Yoga Book 9i on price for the cheapest model and laptops like the MacBook Air 15, spec for spec.

The best recommendation I can give it is that I would put it right at the top of my shortlist if I had this much to spend on a laptop. If offers something genuinely different at a reasonable price, and if this is the future of mobile working, I’m all in.