I tested the KYY X90E laptop screen extender - a heavyweight dual-screen portable monitor with a lightweight price-tag

KYY X90E Portable Monitor: 30-second review

KYY is a Chinese hardware maker specialising in portable displays, and the X90E is one of its latest releases.

Described by the makers as a ‘triple laptop screen extender’, more accurately, this is two monitors in a single package, designed to provide three times the normal screen space when used in conjunction with the monitor that the laptop already has.

Its hinged structure places a 15.6-inch 1080p display to the left and the right of the laptop, and connects via a single USB cable.

It can be configured to mirror the contents, so others can see your laptop display from different viewpoints, or provide an extended desktop.

Power can be sourced directly from the laptop, or for extended use, a small USB-C power supply is included.

The obvious limitation of this platform is that it assumes the laptop has USB-C with an ALT-DP capability or Thunderbolt 3 or 4. And, according to KYY, its designed exclusively for Windows PCs, and doesn’t work with Apple MacBook hardware.

At a little over $300 from the makers, and weighing 2.2kg, any purchaser needs to be convinced that the price and the additional carry are worth it for their productivity.

Despite a few limitations at this price point, it’s an obvious candidate for one of the best portable monitors on a budget that we’ve reviewed.

KYY X90E Portable Monitor: Price and availability

• How much does it cost? $240/£230
• When is it out? It available now
• Where can you get it? Direct from KYY or via online retailers like Amazon

As with previous KYY products, buying directly from the maker isn’t the cheapest way to get the K3 portable monitor. It's selling for $309.99 direct from KYY.

On Amazon.com, it can be found for a standard price of $239.99 - a 20% discount on its official $299.99 list price.

However, on Amazon.co.uk, the same hardware is £229.99, making it slightly more costly to those in the UK. KYY doesn’t sell on the French or German versions of Amazon, but it should be possible to find it in Europe from another online reseller.

Those looking for this hardware should be aware that KYY also makes the X90A and X90D models with different specifications, so make sure you have the X90E variant before clicking the 'buy' button.

Moving away from the KYY brand, there is a collection of remarkably similar products from other Chinese display makers, and some are more expensive, and others slightly cheaper.

Those willing to use 14-inch displays instead of the 15.6-inch displays the X90E offers can be under $200, and ones with three extra displays (making four in total) can be nearer $450.

At the Amazon.com price, this is not a major investment, even if it’s only used sparingly, placing the KYY X90E in the affordable category.

• Value: 4 / 5

KYY X90E Portable Monitor: Specs

KYY X90E Portable Monitor: Design

• Structural integrity
• Various display arrangements
• Single cable connectivity

Out of the box, my first impressions of the X90E were positive. It’s constructed like Soviet-era infrastructure, with a metal skin on all non-display surfaces and two remarkably robust hinges linking the two monitors to a central support plate and foot.

The only downside of the rugged construction is that at 2.2kg, this isn’t a minor item to include in a laptop bag, and you will need one made for a 17-inch laptop to fit it.

When it’s unfolded, the width of the whole unit is a whopping 115cm, although you can make it slightly narrower by adjusting the hinges.

The standard orientation is to place the laptop in the middle and have an extra display on either side, but there are various other options, including rotating them back to provide left and right presentation screens, and also folding one screen away.

You can also use that one screen mode in portrait mode, if you like to mix your orientations.

One curiosity about this solution is that instead of there being one OSD and menu controls, each monitor has its own. I can’t seriously think of a scenario where you would configure one screen to have different brightness, contrast or colour temperature than the other, but this system has that capability.

On the subject of OSD menus, these ones don’t have a large amount of features, and the way they are navigated with buttons is painful. What I fail to understand is that these menus look unchanged from the first ones that appeared on tube monitors twenty-five years ago, same horrible fonts, same insipid colours. The maker's logic appears to be that people will only use it once, so there is little point in making it any better.

In this instance, a menu option to ‘copy to other screen’ might have been a smart choice, but clearly, the menu is something that comes with the display panels, and they’re gloriously unaware of each other.

A feature that I liked much more was that both these displays can be connected using a single USB-C cable to the laptop. That one cable supports ALT-DP to send data to both screens, and also power. The downside of having the one-cable solution is that the screen on a laptop is one of the biggest power consumers, and having three could whittle the battery capacity down rather rapidly.

If you have multiple USB-C ports, you could power the laptop, which might have enough power to drive the external monitors and recharge the battery, or you can use the included 15W PSU to power the monitors directly.

There are only two USB-C inputs on the X90E, one is for connecting and the other is for power, so it’s not possible to give one screen each to two laptops, sadly.

It’s also not on the menu for any laptop that hasn’t got USB-C (or Thunderbolt) or USB-C that supports video output, because there is no HDMI input. While this solution using USB-C is plug and play, requiring no drivers to function, to achieve those standards its exclusively for Windows PCs (7,8.1,10 and 11), and won’t work with Apple MacBook systems.

Overall, the design of the X90E is focused on a specific customer profile who uses a modern Windows laptop with a display between 14-inch and 17-inch. And, while that might seem a little niche, from a percentage viewpoint, it’s a reasonable price for those who might want more screens added to their mobile systems.

• Design: 3.5 / 5

KYY X90E Portable Monitor: Performance

• Better than 300 nits
• 82% sRGB

When comparing these displays, we need to be mindful that these are inexpensive IPS technology panels, and therefore, they can’t hold a candle to OLED or MicroLED technology in terms of contrast and colour representation.

That said, the panels on the X90E were significantly better than those on the KYY K3 I previously tested, suggesting that this maker has developed improved designs.

I’m going to assume that the makers quoted 85% NTSC colour gamut is a misunderstanding, because in my tests, that number was closer to 61%. I suspect it got mixed up with the sRGB, as that’s much closer to 85%.

I say that because while the contrast isn’t the 1200:1 that KYY predicts, the brightness of these panels is almost exactly what they claim.

What information isn’t presented here is the uniformity of luminosity, which isn’t wonderful. The rear illumination of this panel is in the middle, with each of the corners being around 15% less illuminated at 100% brightness.

One curiosity I noticed was that the default White Point on these displays is 7600, not the typical 6500. The OSD doesn’t offer specific temperatures, only ‘cool’, ‘warm’ and ‘user’ definable via R, G and B settings.

Looking at this panel overall, it has decent contrast, gamut and tone response, excellent colour accuracy and uniformity, but suffers from the aforementioned luminance uniformity.

Had the backlighting been more diffuse, this might have been a great result.

I’d summarise the X90E as better than anticipated, but hardly something that those working professionally with colour might gravitate to. But for office work and presentation, in an office with blinds, it's definitely a workable option.

• Performance: 4 / 5

KYY X90E Portable Monitor: Final verdict

I recall being shocked by how usable the KYY K3 was, but the X90E is an even better solution and an implausibly low price. Yes, it’s on the heavy side, and it won’t work with anything other than a Windows laptop with USB-C or Thunderbolt, but it's hard to argue with its value proposition.

An HDMI input to allow another system to share the screens would have been a nice option, or to allow both the USB-C ports to act as inputs. But that these aren’t included, along with speakers at this price point, isn’t a huge surprise.

If you need to triple your screen space and don’t mind another 2.2kg of luggage, then the KYY X90E might be the right choice for you.

KYY X90E Portable Monitor: Report card

Should you buy a KYY X90E Portable Monitor?

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Don’t buy if...

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