TAIPEI—Lenovo plans to sell the first laptop with a built-in 5G modem sometime early next year. In fact, the prototype already exists, and I spent a few minutes with it at Computex this week. Based on what I saw, the world's first 5G laptop holds a lot of promise, but also several potential drawbacks.

There's no official name for the laptop yet, but Lenovo and Qualcomm, which makes the Snapdragon processor that will power it, have named the prototype "Project Limitless." From the outside, the prototype looks like many other Lenovo Yoga-branded laptops currently on sale, including the Yoga C630 and flagship Yoga C930.

Its most unique features are all inside. There's a Snapdragon 8CX processor and a Snapdragon X55 5G modem, which theoretically means much faster performance and higher cellular data speeds than existing Snapdragon-based laptops. The 8CX's CPU has more system cache and twice the memory bandwidth of its Snapdragon 850 predecessor, while the X55 is capable of speeds up to 7GBps.

The result, as I witnessed, is the ability to run multiple apps simultaneously on both the laptop's built-in display and as many as two external 4K monitors. Browser tabs loaded quickly, and video playback is silky smooth. Of course, those are basic things that almost any laptop should be able to accomplish, but existing Snapdragon-powered ones like the Samsung Galaxy Book2 suffer from software limitations that make the user experience slightly sluggish.

In addition to more powerful hardware, software developers have been re-writing apps to run natively on the Snapdragon platform, which will also address the performance issues. This week, Qualcomm announced that the Unity video game engine now runs natively. Most web browsers and Microsoft-made apps already do.

There's even a new version of the PCMark 10 benchmark utility that runs natively, which raises the prospect of direct performance comparisons between Intel- and Snapdragon-powered laptops. No independent test results exist yet, but based on Qualcomm's own internal testing, Microsoft apps like Excel, PowerPoint, Word, and the Edge web browser all perform equally well or better on an 8CX-powered laptop as they do on one with an Intel Core i5.

No Service (Yet)

Snappy performance is all well and good, but the main reason you'd buy a 5G laptop is for the 5G, and that's where things become less promising. Few US cities have 5G coverage, which means that if you buy Lenovo's laptop as soon as it goes on sale, you'll probably be limited to LTE speeds.

Here in Taiwan, the country's main carrier, Chunghwa Telecom, is testing 5G equipment, but nothing is publicly available yet, so I couldn't perform speed tests during Computex. However, Qualcomm did bring along one of Chunghwa's 5G base stations, so I was at least able to see that the laptop does indeed have a 5G connection.

It's clear that for now, the 5G laptop is still very much a prototype. With the power of the 8CX and improved software compatibility, it's on the path to success, but much will depend on how quickly 5G networks come online.