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MagyarLenovo Yoga C940-15IRH Convertible Review: The XPS 15 2-in-1 Dell Should Have Made
The Yoga C900 series is home to Lenovo's premier convertible Ultrabooks. Last year's 13.9-inch Yoga C930 was popular enough that it spawned two successors instead of just one: the 14-inch Yoga C940-14 and the larger 15.6-inch Yoga C940-15. We had already checked out the Yoga C940-14 back in October and so this review will focus on the Yoga C940-15. Nonetheless, we recommend checking out our review on the Yoga C940-14 as this 15.6-inch variant shares the same materials and overall design language as its smaller 14-inch sibling.
The Yoga C940-15 is very different internally when compared to the Yoga C940-14 despite their similar appearances. Instead of an Ice Lake-U CPU, the 15.6-inch model comes with Coffee Lake-H and a GeForce Max-Q GPU for much faster performance. Direct competitors in this space include other 15.6-inch performance multimedia laptops like the Asus ZenBook Pro 15, Dell XPS 15 9570/7590, XPS 15 9575, Gigabyte Aero 15, HP Spectre x360 15, and the Microsoft Surface Book.
More Lenovo reviews:
Rating | Date | Model | Weight | Height | Size | Resolution | Best Price |
|---|---|---|---|---|---|---|---|
| 86 % | 12/2019 | Lenovo Yoga C940-15IRH i7-9750H, GeForce GTX 1650 Max-Q | 2 kg | 19.7 mm | 15.6" | 1920x1080 | |
| 87 % | 08/2019 | Dell XPS 15 7590 9980HK GTX 1650 i9-9980HK, GeForce GTX 1650 Mobile | 2 kg | 17 mm | 15.6" | 3840x2160 | |
| 83 % | 09/2019 | Asus ZenBook 15 UX534FT-DB77 i7-8565U, GeForce GTX 1650 Max-Q | 1.7 kg | 18.9 mm | 15.6" | 1920x1080 | |
| 84 % | 08/2019 | HP Gaming Pavilion 15-dk0009ng i7-9750H, GeForce GTX 1660 Ti Max-Q | 2.4 kg | 23.4 mm | 15.6" | 1920x1080 | |
| 85 % | 11/2019 | MSI Prestige 15 A10SC i7-10710U, GeForce GTX 1650 Max-Q | 1.7 kg | 16 mm | 15.6" | 3840x2160 |
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Case
Lenovo has translated the 14-inch Yoga C940 chassis perfectly for a 15.6-inch form factor. Surfaces do not feel any weaker or more flexible despite the expanded volume for a solid first impression. Attempting to twist the base or lid results in just minor flexing to be in line with the competing XPS 15 or ZenBook 15. Rigidity is a step above the lesser Yoga 730 or 500 series where materials feel thinner, cheaper, and more prone to warping.
Much like last year's Yoga C930, the C940 continues the tradition of a notched bezel and a hinge with integrated speakers. The former provides an easier grip for opening the lid while the latter allows for stronger audio. However, we suspect Lenovo will eventually drop the characteristic notch as webcams have become smaller as exemplified by the latest XPS 13 and HP Spectre 13 designs.
The Lenovo is thicker than the Dell XPS 15 by almost 3 mm while maintaining roughly the same footprint and weight. In return, users get stronger speakers, the added versatility of 360-degree hinges, and an integrated active stylus slot. Traditional clamshell Ultrabooks with ULV CPUs like the Asus ZenBook 15 or Lenovo's own IdeaPad S940 are noticeably lighter and smaller. For a convertible, however, 2 kg feels quite heavy especially if you intend to use the stylus often.
Connectivity
All ports from the 14-inch Yoga C940 are here with an added USB Type-A port along the right edge. We would have liked an SD card reader since both the XPS 15 and ZenBook 15 include one. You'll have to exploit the dual Thunderbolt 3 ports to make the most of the system since port options are fairly limited for a 15.6-inch form factor.
Communication
The Intel AX200 comes standard for Bluetooth 5 and 802.11ax/Wi-Fi 6 connectivity. Transfer rates can reach over two times the typical 802.11ac standard should you have a Wi-Fi 6 router.
| Networking | |
| iperf3 Client (receive) TCP 1 m 4M x10 | |
| MSI Prestige 15 A10SC | |
| Asus ZenBook 15 UX534FT-DB77 | |
| Dell XPS 15 7590 9980HK GTX 1650 | |
| iperf3 Client (transmit) TCP 1 m 4M x10 | |
| MSI Prestige 15 A10SC | |
| Dell XPS 15 7590 9980HK GTX 1650 | |
| Asus ZenBook 15 UX534FT-DB77 | |
Maintenance
A T5 Torx screw is required to pry open the bottom panel. Once inside, users will be able to service the M.2 SSD, WLAN module, and battery. System RAM is soldered.
Accessories and Warranty
There are no included extras in the box aside from the active stylus housed in the laptop itself. A USB Type-C to HDMI adapter would have been appreciated since the system integrates no HDMI ports.
The standard one-year limited warranty applies. Protection can be extended up to four years for an additional $100 USD with on-site coverage options.
Input Devices
Keyboard
Key feedback and size are the same as they are on the 14-inch Yoga C940 but with an integrated NumPad to make use of the roomier 15.6-inch screen size. Unfortunately, the NumPad keys are narrower than the main QWERTY keys and so they do not feel as firm. The keyboards on most ThinkPads like the T590 or X1 Carbon feel more robust with deeper key travel than what the Yoga C940 has to offer. The keys on the competing Spectre x360 15 are firmer and more satisfying to type on as well.
A two-level white keyboard backlight is included. All key labels are illuminated unlike some keys on the Gigabyte Aero series.
Touchpad
The clickpad (10.5 x 7 cm) is slightly smaller than the one on the XPS 15 (10.5 x 8.5 cm). It's also the same size as the clickpad on the smaller 14-inch Yoga C940 and so it's a bit disappointing that Lenovo chose not to utilize the extra space available for a larger surface area. The smooth glide and spongy feedback are also exactly as they are on the smaller 14-inch Yoga C940 for better or worse.
Display
Our unit comes with a 1080p IPS touchscreen which, despite being the base option, is able to offer most features of a pricier panel. The backlight in particular is brighter than most Ultrabooks as our independent measurements can confirm Lenovo's advertisement claim of 500 nits even though uniformity could have been better. Contrast is also better than expected at nearly 1900:1 for better video playback. While the LG Philips LP156WFC panel series can be found on many other 15.6-inch laptops like the Asus VivoBook S15 or Lenovo ThinkPad T590, this specific LP156WFC-SPU1 panel on our Lenovo is the first in our database.
The main drawbacks of the display are the slow black-to-black and gray-to-gray response times. Whereas most desktop monitors offer 5 ms or 8 ms response times, the panel here is at 21 ms for more noticeable ghosting. This isn't an issue if merely word processing or video streaming, but the blurring becomes apparent when playing fast-paced games like Rocket League or most first-person shooters.
| |||||||||||||||||||||||||
Brightness Distribution: 82 %
Center on Battery: 484.8 cd/m²
Contrast: 1865:1 (Black: 0.26 cd/m²)
ΔE Color 4.5 | 0.6-29.43 Ø5.8, calibrated: 1.19
ΔE Greyscale 5.7 | 0.64-98 Ø6
92.8% sRGB (Argyll 3D) 58.7% AdobeRGB 1998 (Argyll 3D)
Gamma: 2.45
| Lenovo Yoga C940-15IRH LG Philips LP156WFC-SPU1, IPS, 15.6, 1920x1080 | Dell XPS 15 7590 9980HK GTX 1650 Samsung 156WR04, SDCA029, OLED, 15.6, 3840x2160 | Asus ZenBook 15 UX534FT-DB77 BOE NV156FHM-N63, IPS, 15.6, 1920x1080 | Lenovo Ideapad 720S-15IKB 81AC001AGE Chi Mei CMN15E8 / N156HCE-EN1 CMN, IPS, 15.6, 1920x1080 | HP Gaming Pavilion 15-dk0009ng LG Philips LGD05FE, IPS, 15.6, 1920x1080 | MSI GP65 Leopard 9SE-225US LG Philips LGD0625, IPS, 15.6, 1920x1080 | HP Spectre x360 15-df0126ng AU Optronics AUO30EB, IPS, 15.6, 3840x2160 | |
|---|---|---|---|---|---|---|---|
| Response Times | 94% | 12% | 31% | 69% | 76% | -2% | |
| Response Time Grey 50% / Grey 80% * | 48.4 (24.4, 24) | 2.3 (1.1, 1.2) 95% | 41.2 (22, 19.2) 15% | 34 (15, 19) 30% | 16.4 (8.4, 8) 66% | 9.6 (6, 3.6) 80% | 57 (26, 31) -18% |
| Response Time Black / White * | 36.4 (21.2, 15.2) | 2.4 (1.1, 1.3) 93% | 33.2 (19.6, 13.6) 9% | 25 (14, 11) 31% | 10.4 (5.2, 5.2) 71% | 10.4 (6, 4.4) 71% | 31 (16, 15) 15% |
| PWM Frequency | 59.52 (100) | 25000 (40) | |||||
| Screen | -1% | -36% | -12% | 5% | 2% | -16% | |
| Brightness middle | 484.8 | 421.2 -13% | 312.6 -36% | 332 -32% | 345 -29% | 348.3 -28% | 330 -32% |
| Brightness | 463 | 417 -10% | 290 -37% | 301 -35% | 324 -30% | 327 -29% | 310 -33% |
| Brightness Distribution | 82 | 94 15% | 85 4% | 83 1% | 86 5% | 85 4% | 87 6% |
| Black Level * | 0.26 | 0.31 -19% | 0.29 -12% | 0.42 -62% | 0.4 -54% | 0.37 -42% | |
| Contrast | 1865 | 1008 -46% | 1145 -39% | 821 -56% | 871 -53% | 892 -52% | |
| Colorchecker DeltaE2000 * | 4.5 | 6.06 -35% | 5.78 -28% | 3.73 17% | 1.3 71% | 1.6 64% | 4.03 10% |
| Colorchecker DeltaE2000 max. * | 7.55 | 11.89 -57% | 8.86 -17% | 6.6 13% | 2.8 63% | 5.07 33% | 6.74 11% |
| Colorchecker DeltaE2000 calibrated * | 1.19 | 3.78 -218% | 2 -68% | 1.1 8% | 1 16% | 1.96 -65% | |
| Greyscale DeltaE2000 * | 5.7 | 2.8 51% | 5.4 5% | 3.96 31% | 1.2 79% | 2.3 60% | 4.49 21% |
| Gamma | 2.45 90% | 2.15 102% | 2.21 100% | 2.4 92% | 2.31 95% | 2.203 100% | 2.57 86% |
| CCT | 6101 107% | 6235 104% | 7864 83% | 6921 94% | 6476 100% | 6707 97% | 6744 96% |
| Color Space (Percent of AdobeRGB 1998) | 58.7 | 81 38% | 57.1 -3% | 58 -1% | 60.5 3% | 61 4% | 61 4% |
| Color Space (Percent of sRGB) | 92.8 | 99.6 7% | 87.4 -6% | 89 -4% | 94.9 2% | 96 3% | 94 1% |
| Total Average (Program / Settings) | 47% /
18% | -12% /
-29% | 10% /
-5% | 37% /
15% | 39% /
13% | -9% /
-13% |
* ... smaller is better
Color space covers approximately 93 percent and 59 percent of the sRGB and AdobeRGB standards, respectively, to be indicative of a mid-range IPS panel. While a 4K UHD IPS option is available for the Yoga C940-15, we're unsure of the exact panel or how its colors compare to our FHD SKU. It's too bad that Lenovo does not offer any OLED options for the Yoga C940-15 in the U.S. unlike on the XPS 15, Razer Blade 15, Gigabyte Aero 15, or Alienware m15.
Further measurements with an X-Rite colorimeter reveal an inaccurate display with poor RGB balance and an overly warm color temperature. Once we calibrated the panel ourselves, average grayscale and color DeltaE values improved dramatically from 5.7 to 1.4 and 3.56 to 0.97, respectively. We recommend an end-user calibration or applying our calibrated ICM profile above to get the most out of the display.
Display Response Times
| ↔ Response Time Black to White | ||
|---|---|---|
| 36.4 ms ... rise ↗ and fall ↘ combined | ↗ 21.2 ms rise |  |
| ↘ 15.2 ms fall | ||
| The screen shows slow response rates in our tests and will be unsatisfactory for gamers. In comparison, all tested devices range from 0.8 (minimum) to 240 (maximum) ms. » 94 % of all devices are better. This means that the measured response time is worse than the average of all tested devices (24.4 ms). | ||
| ↔ Response Time 50% Grey to 80% Grey | ||
| 48.4 ms ... rise ↗ and fall ↘ combined | ↗ 24.4 ms rise |  |
| ↘ 24 ms fall | ||
| The screen shows slow response rates in our tests and will be unsatisfactory for gamers. In comparison, all tested devices range from 0.8 (minimum) to 636 (maximum) ms. » 79 % of all devices are better. This means that the measured response time is worse than the average of all tested devices (38.8 ms). | ||
Screen Flickering / PWM (Pulse-Width Modulation)
| Screen flickering / PWM not detected |  | ||
In comparison: 51 % of all tested devices do not use PWM to dim the display. If PWM was detected, an average of 17699 (minimum: 5 - maximum: 2500000) Hz was measured. | |||
Since the display is brighter than on both the XPS 15 and Spectre x360 15, the Yoga C940-15 is easier to see when outdoors. However, 500 nits is not nearly enough to to completely overpower ambient glare. Certain HP EliteBooks like the 1040 series offer 1000-nit options for better outdoor visibility. Viewing angles are otherwise stable enough for both landscape and portrait orientations. Keep in mind that the sides of the screen will appear dimmer when in portrait mode which is typical on many large IPS panels.
Performance
Currently, the Yoga C940-15 comes in two CPU options (i7-9750H or i9-9880H), two RAM options (12 GB or 16 GB DDR4), two display options (FHD IPS or 4K UHD IPS), and just one GPU. The fact that there are no Core U options shows that Lenovo is targeting performance users who want to do more than just web browsing, video streaming, or emailing. Keep in mind that the system ships with a GTX 1650 Max-Q GPU despite Lenovo failing to mention the term "Max-Q" anywhere on the official product page.
LatencyMon shows no DPC latency issues even when wireless is enabled.
Processor
The Core i7-9750H is performing within 2 percent of the average i7-9750H in our database taken from over 60 other laptops. Users can expect just 10 percent faster performance than last year's Core i7-8750H or just 10 percent slower than the disappointing Core i9-8950HK. Running CineBench R15 Multi-Thread in a loop results in respectable performance sustainability with a dip of just 10 percent over time. Opting for the higher-end SKU with the octa-core Core i9-9880H can bring up to 40 percent faster multi-thread performance assuming that the Yoga chassis can sustain the high clock rates.
See our dedicated page on the Core i7-9750H for more technical information and benchmark comparisons.
System Performance
PCMark scores are generally comparable to the Asus ZenBook 15. The Lenovo uses a slower SSD while the latter has the slower ULV Core U CPU to compensate. We experienced no software or hardware issues during our time the test unit. Strangely, the Power button became inconsistent after resetting Windows as the system would wake and resume uncontrollably.
| PCMark 8 Home Score Accelerated v2 | 4069 points | |
| PCMark 8 Work Score Accelerated v2 | 5359 points | |
Help | ||
Storage Devices
Just one storage bay is available (M.2 2280 PCIe x4) compared to two on some XPS 15 SKUs and most 15.6-inch gaming laptops. Our particular test unit comes with a 512 GB Intel HBRPEKNX0202AL SSD that integrates Intel H10 Optane. Performance is slower than a "proper" dedicated NVMe SSD like the Samsung PM981 since Optane is positioned to be in between SATA and NVMe. Even so, a budget NVMe SSD like the Toshiba KBG30ZMT512G is still able to offer much faster sequential write rates according to AS SSD and CDM benchmarks. You would be better off configuring with a basic entry-level NVMe SSD since Optane technology is still rather pricey per GB.
See our table of HDDs and SSDs for more benchmark comparisons.
| Lenovo Yoga C940-15IRH Intel Optane Memory H10 with Solid State Storage 32GB + 512GB HBRPEKNX0202A(L/H) | Dell XPS 15 7590 9980HK GTX 1650 Toshiba XG6 KXG60ZNV1T02 | Asus ZenBook 15 UX534FT-DB77 Samsung SSD PM981 MZVLB1T0HALR | Lenovo Ideapad 720S-15IKB 81AC001AGE Samsung SSD PM981 MZVLB512HAJQ | HP Gaming Pavilion 15-dk0009ng Samsung SSD PM981 MZVLB256HAHQ | MSI GP65 Leopard 9SE-225US Toshiba KBG30ZMT512G | |
|---|---|---|---|---|---|---|
| AS SSD | 99% | 75% | 139% | 27% | -17% | |
| Copy Game MB/s | 968.52 | 1823.85 88% | 1287.32 33% | 399.89 -59% | 581.52 -40% | |
| Copy Program MB/s | 455.84 | 983.98 116% | 468.05 3% | 371.74 -18% | 309.51 -32% | |
| Copy ISO MB/s | 838.83 | 3182.39 279% | 1375.25 64% | 1042.93 24% | 992.71 18% | |
| Score Total | 2024 | 3638 80% | 3483 72% | 4771 136% | 2014 0% | 1940 -4% |
| Score Write | 1084 | 1693 56% | 1664 54% | 1581 46% | 819 -24% | 400 -63% |
| Score Read | 618 | 1294 109% | 1210 96% | 2125 244% | 810 31% | 1036 68% |
| Access Time Write * | 0.137 | 0.039 72% | 0.075 45% | 0.039 72% | 0.038 72% | 0.223 -63% |
| Access Time Read * | 0.071 | 0.05 30% | 0.034 52% | 0.042 41% | 0.093 -31% | 0.231 -225% |
| 4K-64 Write | 947.63 | 1456.13 54% | 1374.95 45% | 1281.75 35% | 587.71 -38% | 246.8 -74% |
| 4K-64 Read | 471.98 | 1077.98 128% | 969.22 105% | 1823.43 286% | 564.81 20% | 878.09 86% |
| 4K Write | 100.88 | 98.3 -3% | 146.01 45% | 99.81 -1% | 96.52 -4% | 80.34 -20% |
| 4K Read | 69.08 | 43.25 -37% | 52.32 -24% | 54.26 -21% | 36.14 -48% | 27.58 -60% |
| Seq Write | 351.12 | 1386.27 295% | 1432.22 308% | 1990.72 467% | 1346.75 284% | 730.48 108% |
| Seq Read | 769.21 | 1723.09 124% | 1886.9 145% | 2468.59 221% | 2087.58 171% | 1307.09 70% |
| CrystalDiskMark 5.2 / 6 | 50% | 63% | 59% | 14% | -26% | |
| Write 4K | 102.2 | 104.3 2% | 141.6 39% | 139.3 36% | 100 -2% | 99.35 -3% |
| Read 4K | 114.3 | 45.23 -60% | 45.28 -60% | 46.78 -59% | 31.39 -73% | 46.96 -59% |
| Write Seq | 468.3 | 1729 269% | 1975 322% | 2125 354% | 1308 179% | |
| Read Seq | 1236 | 1861 51% | 2272 84% | 2354 90% | 1083 -12% | |
| Write 4K Q32T1 | 555.7 | 509.2 -8% | 458.6 -17% | 298.4 -46% | 362.9 -35% | 240.1 -57% |
| Read 4K Q32T1 | 421.6 | 388.5 -8% | 391.4 -7% | 355.8 -16% | 425.7 1% | 580.9 38% |
| Write Seq Q32T1 | 1264 | 2813 123% | 2393 89% | 2128 68% | 1411 12% | 686 -46% |
| Read Seq Q32T1 | 2239 | 2906 30% | 3464 55% | 3324 48% | 3240 45% | 1581.2 -29% |
| Write 4K Q8T8 | 268.1 | |||||
| Read 4K Q8T8 | 976.8 | |||||
| Total Average (Program / Settings) | 75% /
81% | 69% /
70% | 99% /
105% | 21% /
23% | -22% /
-19% |
* ... smaller is better
GPU Performance
The GTX 1650 Max-Q is only about 7 to 15 percent slower than our desktop GTX 1650 reference or about 10 to 30 percent faster than the mobile GTX 1050 Ti. Thus, the Yoga C940-15 is wholly capable of playing the latest games even though it is not technically a gaming laptop. Had Lenovo offered a GTX 1660 Ti Max-Q option, gaming performance would have been up to 50 percent faster. Be sure to enable DX12 if available since Nvidia Turing GPUs are optimized for Microsoft's latest API.
| 3DMark 11 Performance | 11952 points | |
| 3DMark Cloud Gate Standard Score | 29013 points | |
| 3DMark Fire Strike Score | 7717 points | |
| 3DMark Time Spy Score | 3494 points | |
Help | ||
Gaming Performance
The GTX 1650 Max-Q may be one of the slowest GTX Turing GPUs available, but it's still able to punch above its weight class to be on par with the popular GTX 1060. Even the latest demanding titles can run smoothly at 1080p with most settings set to High or Maximum. We recommend engaging v-sync since frame rates tend to hover between 30 and 60 FPS.
It's interesting to note that the MSI Prestige 15 with a 15 W hexa-core CPU and same GTX 1650 Max-Q GPU performs about 20 percent slower in Shadow of the Tomb Raider. It's likely that most games will still run better on a 9th gen quad-core Core H laptop than a 10th gen hexa-core Core U laptop when given the same GPU.
See our dedicated page on the GeForce GTX 1650 Max-Q for more technical information and benchmark comparisons.