Lenovo Yoga C640 – Review 2020

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.