ASUS ZenBook Pro UX550 is a powerhouse with a 4K touchscreen

A slick design stuffed with Intel's top mobile CPU and a discrete GPU.

It's been over two years since ASUS announced its original ZenBook Pro, and while the machine received a spec bump late last year, it's about time for the company to revamp its premium desktop replacement line. Announced at the "Edge of Beyond" event ahead of Computex, the new ZenBook Pro UX550 once again dons a 15.6-inch 4K touchscreen behind the spin-metal lid, except this time it comes with Intel's top Kaby Lake option plus an NVIDIA GTX 1050 Ti graphics chip (with 4GB of DDR5 VRAM). More notably, at 18.9mm thick and 1.8kg (3.97 pounds), the UX550 is one of the most portable laptops in its class, beating the Dell Inspiron 15 7000 (25.44mm/2.62kg) and Acer Nitro 5 (26.75mm/2.7kg), which tout similar specs (except for their lack of 4K display option), while almost matching the smaller 14-inch Razer Blade (17.9mm/ 1.86kg).

Compared to its predecessor, the UX550 is able to make better use of its 4K display thanks to its quad-core Kaby Lake CPUs; both the top-tier Core i7-7700HQ (2.8GHz to 3.8GHz; eight threads, 6MB cache) and the Core i5-7300HQ (2.5GHz to 3.5GHz; four threads, 6MB cache) feature dedicated 4K HEVC support, meaning they can process 4K video more efficiently. The UX550 has traded one of the old USB Type-A ports for a second Type-C port next to the full-size HDMI 1.4 port, and with both Type-C ports supporting the Thunderbolt 3 spec (up to 40 Gbps), this laptop can handle dual 4K video output and power delivery.

The notebook's own 4K display has the same 72-percent NTSC color gamut and 178-degree viewing angle as before, though this time it has a slimmer 7.3mm bezel, which has helped shave 18mm off the previous body width. But there is a trade-off: ASUS decided to remove the numeric keypad, likely because it thinks not many people need this feature these days. Another downside -- though probably unrelated -- is that the old full-size SD card slot is now just a microSD reader, which will be a nuisance for people like me who still use SD cards in their cameras.

On a brighter note, the UX550 has a denser battery rated for a whopping 12 to 14 hours worth of juice -- almost double the runtime of the older model. In addition, its quick charging can take it from zero to 60 percent in just 49 minutes. It can be configured with up to 16GB of DDR4-2400 RAM and up to 1TB of PCIe x4 SSD storage. There's also a new dual-fan cooling system to keep the CPU and GPU well-behaved. Another nice upgrade is the Harman/Kardon-certified quad-speaker audio system -- one driver on each side of the backlit keyboard (with 1.5mm key travel) and two beneath the trackpad. Speaking of, the multitouch glass trackpad has gained a fingerprint reader in the upper-right corner.

Based on my brief hands-on time with the UX550, it feels like a laptop that can go toe-to-toe with the MacBook Pro. The 4K screen looks bright and bold, and the keyboard is a huge improvement from what we typically see from ASUS. Its case is also solid and well constructed, nothing like the ZenBook 3 from last year. The big takeaway: ASUS seems to have learned a lot over the past few years when it comes to building a refined laptop.

The ZenBook Pro UX550 is launching in July with either Windows 10 Pro or Windows 10 Home, starting at $1,299.

Devindra Hardawar contributed to this report.

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