Lenovo ThinkPad L390 Yoga (Core i5-8265U, 256 GB, FHD) Convertible Review

The L390 Yoga has a 13.3-inch IPS touchscreen display that operates natively at 1,920 x 1,080. The panel also has a pixel density of 166 PPI and a 16:9 aspect ratio. Unfortunately, Lenovo does not offer an optional UHD or WQHD panel.

Our review unit achieved an average maximum brightness of 295 cd/m², which is just shy of the 300 cd/m² that Lenovo details in the L390 Yoga spec sheet. The display achieved 300 cd/m² or brighter at two points of the display though. The L390 Yoga finishes second in our comparison table here, but it is 5% darker than its predecessor. The two ThinkPad L Yoga series convertibles share the same black value, which results in the L390 Yoga achieving a 1,423:1 contrast that again puts it second to the L380 Yoga in our comparison table.

Positively, our test device suffers from hardly any backlight bleeding, which is better than many other laptops that we have tested. Moreover, while the L390 Yoga uses pulse-width modulation (PWM) to regulate its display luminosity, which can cause eyestrain and headaches for some people, the frequency is so high it should not trouble even those who are PWM sensitive. We measured a PWM frequency of 1,000 Hz, for reference.

Colors look vibrant on our test device thanks to its good contrast ratio, but its Delta E-2000 deviations were too high upon delivery. The L380 Yoga struggled in this regard too, but the L390 Yoga’s are even higher. We significantly improved our review unit’s color accuracy with further calibration though, the associated ICC profile of which we have included in the box above our comparison table. Please note that for some reason our ICC profile caused the average maximum display luminosity to drop to 250 cd/m², which is 18% darker than without the profile applied.

The L390 achieved slightly lower color space coverage than its predecessor, with its 59.1% AdobeRGB and 90.6% sRGB coverages meaning that the display is only accurate enough for hobbyist image editing. We would recommend considering a more color accurate device if you are a professional user.

The Core i5-8265U is a quad-core processor that can execute up to 8 threads thanks to Intel Hyperthreading. The CPU has a 1.6 GHz base clock speed that can Turbo Boost up to 3.9 GHz on one core and 3.7 GHz across all cores when required.

The Core i5-8265U succeeds the popular Core i5-8250U and predictably delivers better performance in synthetic benchmarks. Our review unit achieved up to 12% better single-core performance than its predecessor and 22% in multi-threaded benchmarks like Cinebench R15 Multi 64Bit.

We also subjected our test device to a looped CB R15 Multi 64Bit benchmark to determine how well it can maintain its peak CPU performance under sustained load. Please note that we had HWiNFO logging system information throughout our looped benchmark, which is why the L390 Yoga achieved lower peak CB R15 scores than it did in our initial tests.

The CPU can consume up to 51 W for 28 seconds, but its core temperatures rapidly rose to 90 °C (194 °F) during our tests, at which point our review unit started to thermal throttle. You can see how hard the system throttles in the graph below, with the benchmark dropping by 100 points in the second run through. The CPU had cooled sufficiently by the fifth benchmark in which it scored 563 points, but the scores gradually dropped to 525 points by the end of the loop. In short, the L390 Yoga achieved considerably higher scores than its predecessor, and many of our other Core i5-8250U equipped comparison devices, but it is on par with the Inspiron 13 5379, despite the latter having a theoretically weaker processor.

Please see our CPU benchmarks page for more information about the Core i5-8265U and how it compares against other processors.

Lenovo equipped our test device with a 256 GB Samsung PM981 SSD, which is faster than the drives in our comparison devices. The PM981 is a PCIe drive that utilizes the NVMe protocol, which helps it achieve fast sequential transfer speeds of over 1 GB/s. By contrast, the Inspiron 13 5379 has a Micron 1100 SSD that cannot exceed 600 MB/s because it operates on the much slower SATA III standard.

The PM981 also has excellent 4K read speeds of over 50 MB/s, which should ensure that programs and the OS load quickly. Please see our HDD/SSD benchmarks page for more information about the PM981 and how it compares against other drives.

The L390 Yoga uses a single heat pipe and fan to cool its CPU, but the system operates almost silently while idling. The fan occasionally spins up, but it only reaches a maximum of 30.6 dB(A) under load, which is comparatively quiet even for a convertible laptop. In short, the L390 Yoga has one of the quietest active cooling systems that we tested.

We should also note that we noticed no coil whine or any other electrical interference during our tests.

Unfortunately, the L390 Yoga’s speakers are in the same position as its predecessor. The downward firing stereo speakers are simply too quiet and lack bass, although the latter is an issue that the convertible shares with most laptops. Audio sounds comparatively balanced, but Lenovo equips its other devices, like the Yoga C930, with better speakers. The latter has speakers that are integrated within its 360 ° hinge, which helps it deliver richer sound than the L390 Yoga can. If Lenovo equips future ThinkPad Yogas with similar speakers, then nothing should stand in the way of us awarding a better rating in this regard.

Alternatively, you could connect external speakers or headphones via Bluetooth or the headphone jack for a better listening experience. The latter worked perfectly throughout our tests.