A bold experiment with Qualcomm Snapdragon processors made Lenovo’s midrange Yoga C600 series one of the most intriguing laptops of 2019. But the Yoga C630 suffered from app compatibility issues and sluggish performance, and Lenovo decided to switch back to an Intel Core i3 for the new Yoga C640 reviewed here. Although performance is still tepid, this 2-in-1 convertible laptop is lightweight, well-built, and offers extraordinary battery life. At $599 for the entry-level configuration we tested, it will appeal to budget-minded shoppers looking for a sensible, long-lasting laptop that they can occasionally convert into a tablet.
Laptop, Tablet, Easel
The Yoga C640 shares a 360-degree convertible hinge with many (but not all) laptops in the Yoga series. That means you can use it as a tablet or an easel by rotating the hinge past 180 degrees, or you can use it as a conventional laptop. Unlike detachable 2-in-1s, which are more similar to the Apple iPad, convertible designs have their keyboards permanently attached, which means they’re suited to occasional tablet use but will spend most of their time in laptop mode.
Our Yoga C640 review unit comes with a 13.3-inch, full HD (1,920-by-1,080-pixel) display. That’s the only screen option, unlike the more expensive Yoga C740 and Yoga C940, which all offer multiple larger screen sizes. Lenovo also sells convertible versions of its business-focused ThinkPad lineup at multiple prices and screen sizes, including our current Editors’ Choice pick for midrange 2-in-1 convertibles, the ThinkPad L13 Yoga.
Like its screen size, the Yoga C640’s Iron Gray aluminum and fiberglass color scheme is also non-negotiable. It’s subtle and refined, not distinctive or futuristic.
You do have more choices when it comes to the Yoga C640’s internal components, though. The entry-level configuration reviewed here—sold only at Best Buy—comes with a 128GB solid-state drive and an Intel Core i3-10110U processor with a base clock speed of 2.1GHz. An upgraded Core i5 model with a larger 256GB SSD is also available directly from Lenovo. Both versions use Intel’s latest 10th-generation U-series processors and 8GB of memory.
An Ideal Travel Companion
The Yoga C640’s 13.3-inch screen makes it a great traveling partner. It’s not so small that you’ll be squinting at it, but it’s not so large or heavy that you’ll struggle to stuff it into your backpack or hold it with one hand as a tablet. The laptop measures 0.67 by 12.05 by 8.05 inches and weighs 2.98 pounds. Those are competitive dimensions even among 13-inch non-convertible clamshells, like the Apple MacBook Air (0.63 by 11.97 by 8.46 inches and 2.8 pounds).
The in-plane switching (IPS) screen offers touch support, along with reasonably crisp text and enjoyable colors. It’s rated for a relatively common 300 nits of brightness, which is less than the 500-nit maximums of many more expensive laptops, but still plenty bright enough to be viewed in a well-lit room. The glossy screen has a finish that Lenovo says reduces glare from ambient lighting.
Above the display is a 720p webcam with sliding privacy shutter. The shutter is very well integrated and barely noticeable, regardless of whether it’s closed or open. The camera offers slightly grainy video and noisy images even in good lighting conditions, but it’s no worse than most other webcams, even ones on laptops that cost much more.
The camera lacks IR sensors for face recognition, but you can still log into Windows Hello using the fingerprint reader mounted on the keyboard deck. The keyboard itself offers slightly disappointing typing comfort—it’s decent by general laptop standards, but below the level that many people expect from Lenovo, maker of the legendary ThinkPad keyboards. The C640’s keys are a bit wobbly when you strike them off center, and they emit a cheap-feeling clicking sound rather than the satisfying thunk that the best ThinkPad T- and X-series keyboards make.
The Yoga’s touchpad is a bit cramped, though to Lenovo’s credit it fills the distance between the bottom of the keyboard and the front edge of the laptop. There’s simply no room to make it larger.
Need USB-A? Yoga’s Got You Covered
The Yoga C640’s port selection is far from plentiful, but its two USB 3.1 Type-A ports (one on each side) are relatively generous at a time when many similarly sized laptops are ditching these ports entirely. They’ll come in handy for connecting charging cables for smart watches, e-readers, and transmitters for wireless mice, many of which still use this aging port. The laptop also includes a single USB 3.1 Gen 1 Type-C port, the oval-shaped connector that is the way of the future for peripheral connections.
The laptop lacks a dedicated video output, but the USB-C port can connect to an external monitor with the help of an HDMI or DisplayPort adapter or dongle. A power connector and a 3.5mm audio output/input combo jack round out the port selection. There’s no Thunderbolt 3 port or SD card reader, though we don’t expect to see these on a general-purpose laptop at this price.
Wireless connections include 802.11ac Wi-Fi and Bluetooth 5.0. The lack of the latest 802.11ax (Wi-Fi 6) standard might be a concern if you plan to upgrade your home router in the near future, but for now the 802.11ac spec should be adequate for most users.
The Yoga C640’s stereo speakers pipe audio through two rectangular grilles that flank the keyboard. This is a rather common audio setup for laptops, and it produces adequate sound when the laptop is used in the conventional orientation, since the speakers are facing you. But if you prop the Yoga up like a tent or use it as a tablet, the speaker grilles will be facing away from you, which tends to muffle the sound a bit.
Lenovo’s premium convertibles like the Yoga C940 offer ingenious solutions for this problem, including turning the entire hinge into a sound bar that rotates with the display so it’s always facing you. If you care a great deal about your laptop’s audio quality, you’ll want to look at these more expensive models instead of the C640.
Intel Core i3: Only Adequate Performance
The switch to Intel processors lets this Yoga ditch the app-compatibility issues and other teething problems of the nascent Qualcomm chips, including the Snapdragon 850 in the Yoga C630. In the entry-level Core i3 configuration, the Yoga C640 is far from a computing powerhouse, but at least it’s no more sluggish than its predecessor was.
The Core i3 also puts the C640 at a slight disadvantage to comparable laptops in the same price range, most of which use Core i5 CPUs. A few examples include the Dell Inspiron 14 5000 and Inspiron 13 5000 clamshells and the Yoga C740 2-in-1. The Microsoft Surface Go 2 detachable tablet is also comparable in price, but uses a slower Core m3 processor.
During my time with the Yoga C640 I experienced a few hangs and lags when installing apps, resizing windows, and loading very large video files, but I find that general web browsing and other similar tasks worked just fine. I did notice that the Yoga’s cooling fan spooled up frequently, even when I was transferring files to and from an external drive. You will certainly hear the fan in a quiet room. The Yoga C630, in contrast, has no fan at all, since the Snapdragon 850 does not require active cooling. (See how we test laptops.)
Overall, the Yoga C640 benchmarked as expected. In the PCMark 10 test, it proved faster than the Core m3-powered Surface Go 2, but slower than the Core i5-based Dell Inspirons and Yoga C740.
PCMark 10 simulates different real-world productivity and content-creation workflows. We use it to assess overall system performance for office-centric tasks such as word processing, spreadsheet jockeying, web browsing, and videoconferencing. The PCMark 8 test is similar, but isolates the performance contribution of the laptop’s boot drive; since all of the systems above have SSDs, they all performed roughly equally in that test.
Multimedia content creation tasks are more taxing for a laptop’s CPU, and probably something you want to avoid using the Yoga C640 for as your primary pursuit. The difference between it and the Core i5 systems was significant in the CPU-crunching Cinebench R15 test, a 3D rendering exercise that’s fully threaded to make use of all available processor cores and threads.
The C640 was also at a disadvantage when it came to video encoding, as shown by our Handbrake test, which involves transcoding a 12-minute clip of 4K video to a 1080p MP4 file.
But the laptop fared a bit better when editing images in Adobe Photoshop, with scores in our Photoshop benchmark that were much more comparable to those of the Core i5 systems.
Gaming is possible on the Yoga C640, but you’ll want to stick to browser-based games or titles with light computing demands like Minecraft or Counter-Strike: Global Offensive. The laptop doesn’t approach the 30-frame-per-second threshold for acceptable gaming performance on demanding AAA titles, as our 3DMark and Unigine Superposition benchmarks show. Still, none of the other comparable laptops does, either. (These tests render and pan through detailed 3D scenes and measure how the systems cope. Driver issues with the Inspiron 14 5000 prevented it from completing the 3DMark test).
Battery life is one of the key strengths of the power-sipping Snapdragon chips like the one in the Yoga C630, and Snapdragon-powered laptops are often advertised as being able to spend several days of typical use without needing to be plugged in. But the Intel Core-based Yoga C640 also offers excellent battery life. This is thanks in part to a generously sized 60WHr battery and in part to improvements to Intel’s 10th generation chips that better position them to rival the power efficiency of Qualcomm’s.
As a result, the C640 lasted for more than 21 hours in our video rundown test, which involves playing a locally stored 720p video file at 50 percent screen brightness with Wi-Fi and Bluetooth turned off. This is significantly more than most competing ultraportables, and also longer than the Yoga C630, which lasted for 17 hours and 38 minutes in our test.
A Better Way to Budget
Overall, the Yoga C640 is a well-priced 2-in-1 convertible whose nifty features, like an integrated webcam privacy filter, are nice to have. Perhaps its signature feature is remarkable battery life, which will appeal to buyers who plan to spend a lot of time away from a power outlet.
Its Core i3 CPU hampers computing performance somewhat, however, echoing the drawbacks of the preceding Yoga C630, which Lenovo continues to sell. So if you have a bit more money to spend, it’s worth taking a look at the ThinkPad L13 Yoga or the Dell XPS 13 2-in-1, our current top picks for convertible laptops.
Lenovo Yoga C640 Specs
| Laptop Class | Convertible 2-in-1 |
| Processor | Intel Core i3-10110U |
| Processor Speed | 2.1 GHz |
| RAM (as Tested) | 8 GB |
| Boot Drive Type | SSD |
| Boot Drive Capacity (as Tested) | 128 GB |
| Screen Size | 13.3 inches |
| Native Display Resolution | 1,920 by 1,080 |
| Touch Screen | Yes |
| Panel Technology | IPS |
| Variable Refresh Support | None |
| Screen Refresh Rate | 60 Hz |
| Graphics Processor | Intel UHD Graphics |
| Wireless Networking | 802.11ac, Bluetooth |
| Dimensions (HWD) | 0.67 by 12.05 by 8.05 inches |
| Weight | 2.98 lbs |
| Operating System | Windows 10 |
