Dell Inspiron 15 5578-1777 Convertible Review
For the original German review, see here.
The Dell Inspiron 15 5578-1777 is a 15.6-inch convertible laptop. This is the sister model of the structurally identical Inspiron 15 5568 that we have recently reviewed. One of the differences between the devices is their processors: While the 5578-1777 is equipped with a Kaby Lake processor, the sister model has a Skylake CPU on board. The Inspiron's competition consists of laptops such as the HP Pavilion x360 15 and the Lenovo Yoga 510-15ISK.
Since the two Inspiron models that we have chosen to review are structurally identical, we will not cover the case, connectivity options, input devices or speakers in this article. Please see our review of the Inspiron 15 5568 for information on these subjects.
| SD Card Reader | |
| average JPG Copy Test (av. of 3 runs) | |
| Lenovo Yoga 510-15ISK | |
| HP Pavilion x360 15-bk102ng | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| Dell Inspiron 15 5568 | |
| maximum AS SSD Seq Read Test (1GB) | |
| HP Pavilion x360 15-bk102ng | |
| Lenovo Yoga 510-15ISK | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| Dell Inspiron 15 5568 | |
| Networking | |
| iperf3 transmit AX12 | |
| HP Pavilion x360 15-bk102ng | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| iperf3 receive AX12 | |
| HP Pavilion x360 15-bk102ng | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| iperf Client (transmit) TCP 1 m | |
| Dell Inspiron 15 5568 | |
| iperf Server (receive) TCP 1 m | |
| Dell Inspiron 15 5568 | |
Display
The Inspiron's 15.6-inch touchscreen display has a native resolution of 1920x1080 pixels. The screen offers a good contrast ratio (976:1). The brightness, on the other hand, is too low (242.3 cd/m²). A convertible laptop in this price range should provide at least 300 cd/m² of luminance. On a positive note, we never experienced any PWM backlight flickering with this display.
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Brightness Distribution: 93 %
Center on Battery: 244 cd/m²
Contrast: 976:1 (Black: 0.25 cd/m²)
ΔE Color 4.94 | 0.5-29.43 Ø4.91
ΔE Greyscale 4.93 | 0.5-98 Ø5.2
63% sRGB (Argyll 1.6.3 3D)
40% AdobeRGB 1998 (Argyll 1.6.3 3D)
43.13% AdobeRGB 1998 (Argyll 2.2.0 3D)
62.8% sRGB (Argyll 2.2.0 3D)
41.74% Display P3 (Argyll 2.2.0 3D)
Gamma: 2.7
| Dell Inspiron 15 5578-1777 2-in-1 IPS, 1920x1080, 15.6" | Dell Inspiron 15 5568 IPS, 1920x1080, 15.6" | HP Pavilion x360 15-bk102ng IPS, 1920x1080, 15.6" | Lenovo Yoga 510-15ISK IPS, 1920x1080, 15.6" | |
|---|---|---|---|---|
| Display | -9% | -5% | 2% | |
| Display P3 Coverage | 41.74 | 38.04 -9% | 39.45 -5% | 42.58 2% |
| sRGB Coverage | 62.8 | 57.1 -9% | 59.2 -6% | 63.9 2% |
| AdobeRGB 1998 Coverage | 43.13 | 39.3 -9% | 40.76 -5% | 43.99 2% |
| Response Times | 7% | -15% | -17% | |
| Response Time Grey 50% / Grey 80% * | 55 ? | 42 ? 24% | 55 ? -0% | 43.2 ? 21% |
| Response Time Black / White * | 20 ? | 22 ? -10% | 26 ? -30% | 30.8 ? -54% |
| PWM Frequency | 50 ? | |||
| Screen | -3% | -28% | 2% | |
| Brightness middle | 244 | 266 9% | 205 -16% | 254 4% |
| Brightness | 242 | 249 3% | 191 -21% | 230 -5% |
| Brightness Distribution | 93 | 85 -9% | 74 -20% | 86 -8% |
| Black Level * | 0.25 | 0.26 -4% | 0.3 -20% | 0.26 -4% |
| Contrast | 976 | 1023 5% | 683 -30% | 977 0% |
| Colorchecker dE 2000 * | 4.94 | 4.98 -1% | 7.2 -46% | 4.23 14% |
| Colorchecker dE 2000 max. * | 7.3 | 11.82 -62% | 12.7 -74% | 9.5 -30% |
| Greyscale dE 2000 * | 4.93 | 2.68 46% | 6.86 -39% | 2.87 42% |
| Gamma | 2.7 81% | 2.27 97% | 2.27 97% | 2.35 94% |
| CCT | 7401 88% | 6583 99% | 6983 93% | 5965 109% |
| Color Space (Percent of AdobeRGB 1998) | 40 | 36 -10% | 38 -5% | 40.35 1% |
| Color Space (Percent of sRGB) | 63 | 57 -10% | 59 -6% | 63.48 1% |
| Total Average (Program / Settings) | -2% /
-3% | -16% /
-22% | -4% /
-1% |
* ... smaller is better
Screen Flickering / PWM (Pulse-Width Modulation)
| Screen flickering / PWM not detected | ||
In comparison: 53 % of all tested devices do not use PWM to dim the display. If PWM was detected, an average of 8705 (minimum: 5 - maximum: 343500) Hz was measured. | ||
In factory default setting, the display's DeltaE 2000 color difference is 4.94 - not bad. Manufacturers should strive for a difference of less than 3. The screen does not suffer from a blue cast.
Display Response Times
| ↔ Response Time Black to White | ||
|---|---|---|
| 20 ms ... rise ↗ and fall ↘ combined | ↗ 4 ms rise |  |
| ↘ 16 ms fall | ||
| The screen shows good response rates in our tests, but may be too slow for competitive gamers. In comparison, all tested devices range from 0.1 (minimum) to 240 (maximum) ms. » 39 % of all devices are better. This means that the measured response time is similar to the average of all tested devices (20.9 ms). | ||
| ↔ Response Time 50% Grey to 80% Grey | ||
| 55 ms ... rise ↗ and fall ↘ combined | ↗ 20 ms rise |  |
| ↘ 35 ms fall | ||
| The screen shows slow response rates in our tests and will be unsatisfactory for gamers. In comparison, all tested devices range from 0.165 (minimum) to 636 (maximum) ms. » 91 % of all devices are better. This means that the measured response time is worse than the average of all tested devices (32.8 ms). | ||
Dell's Inspiron offers an IPS panel with stable viewing angles, allowing the user to view the screen content from any angle. Unfortunately, the convertible laptop cannot really be used outdoors: the reflective display surface combined with the panel's low brightness are prohibitive here.
Performance
Dell's Inspiron is a 15.6-inch convertible laptop. The Kaby Lake processor has more than enough performance power to handle all the usual applications. Our test device carries a price tag of about 800 Euros (~$850, gross price). As of the publication of this review we could find only one other version of this device, fitted with a Core i7 processor, more memory and a larger SSD.
Processor
Dell's convertible laptop is equipped with a Core i5-7200U (Kaby Lake) dual-core processor. This is Intel's current mid-range ULV CPU (TDP: 15 watts). It should have ample performance power to meet the demands of most users. Alternatively, Dell is also offering a version of the Inspiron with the somewhat more powerful Core i7-7500U processor. For most users, the slight gain in performance power would not be worth the significantly higher cost. Our model's Core i5 processor runs at a base clock speed of 2.5 GHz. Using turbo, it is possible to reach speeds of up to 3.1 GHz (both cores). The processor takes advantage of its turbo in both AC power mode and battery mode.
| Cinebench R10 | |
| Rendering Multiple CPUs 32Bit | |
| HP Pavilion x360 15-bk102ng | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| Lenovo Yoga 510-15ISK | |
| Rendering Single 32Bit | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| Lenovo Yoga 510-15ISK | |
| Geekbench 3 | |
| 32 Bit Single-Core Score | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| Lenovo Yoga 510-15ISK | |
| 32 Bit Multi-Core Score | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| Lenovo Yoga 510-15ISK | |
| Geekbench 4.0 | |
| 64 Bit Single-Core Score | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| 64 Bit Multi-Core Score | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| JetStream 1.1 - Total Score | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| Dell Inspiron 15 5568 | |
| Lenovo Yoga 510-15ISK | |
System Performance
The combination of a fast solid-state disk and powerful processor produce a fast system. The Inspiron's good score in the PC Mark benchmark demonstrates strong overall performance. The computer also achieved good scores when we ran more demanding applications than simple office and internet-related programs. A slight improvement in the device's overall performance would be possible if the user were to install a second RAM module - then the active dual-channel mode would increase the system's graphics performance.
| PCMark 8 Home Score Accelerated v2 | 3446 points | |
Help | ||
| PCMark 8 - Home Score Accelerated v2 | |
| Lenovo Yoga 510-15ISK | |
| Dell Inspiron 15 5568 | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
Storage Devices
A solid-state drive from SanDisk serves as the computer's system storage device. The SSD is a 2.5-inch model with a total capacity of 256 GB; about 200 GB of which is available to the user. The remaining disk space is occupied by the Windows installation and the recovery partition. The drive's transfer rates are good.
| Dell Inspiron 15 5578-1777 2-in-1 SanDisk X400 256GB, SATA (SD8SB8U-256G) | Dell Inspiron 15 5568 Toshiba THNSNK256GCS8 | HP Pavilion x360 15-bk102ng WDC Slim WD10SPCX-21KHST0 | Lenovo Yoga 510-15ISK Liteonit CV3-DE256 | |
|---|---|---|---|---|
| CrystalDiskMark 3.0 | -4% | -91% | 6% | |
| Read Seq | 503 | 458.6 -9% | 102.4 -80% | 487 -3% |
| Write Seq | 465.3 | 270 -42% | 102 -78% | 450.7 -3% |
| Read 512 | 293 | 397.4 36% | 31.37 -89% | 384.5 31% |
| Write 512 | 322.7 | 242 -25% | 48.12 -85% | 356.3 10% |
| Read 4k | 28.9 | 19.88 -31% | 0.357 -99% | 27.05 -6% |
| Write 4k | 55 | 86.7 58% | 1.047 -98% | 63.7 16% |
| Read 4k QD32 | 314.5 | 275.3 -12% | 0.844 -100% | 281.5 -10% |
| Write 4k QD32 | 209.2 | 197.6 -6% | 1.098 -99% | 232 11% |
Graphics Card
The Inspiron is not equipped with a dedicated GPU; instead Dell has installed Intel's HD Graphics 620 integrated graphics solution. This card supports DirectX 12 and runs at speeds of up to 1000 MHz. The results in the 3D Mark 2011 benchmark are normal for this GPU. Installing a second RAM module would boost the system's performance by activating dual-channel mode.
| 3DMark 11 Performance | 1528 points | |
Help | ||
| 3DMark 11 - 1280x720 Performance GPU | |
| Lenovo Yoga 510-15ISK | |
| Dell Inspiron 15 5568 | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
Gaming Performance
The Inspiron's hardware is powerful enough to run a lot of games smoothly - although mostly games that do not demand too much of the hardware. Even with these games, users will have to be content with a low resolution and low quality settings. The installation of a second RAM module (active dual-channel mode) could increase the frame rates by an average of 20 to 30%. The exact percentage is dependent on the game. A taxing game such as “Watch Dogs 2”, however, is simply unplayable.
| low | med. | high | ultra | |
|---|---|---|---|---|
| BioShock Infinite (2013) | 40.3 | 24.3 | 19.9 | 6.3 |
| Civilization VI (2016) | 26.8 | 9.2 |
Emissions and Energy
The Inspiron is relatively quiet under any level of load. The fan stands still as a general rule, and the rest of the system operates in silence. Even under load the fan does not generate too much noise. During our stress test, we recorded a maximum sound pressure level of 35.3 dB(A).
Noise Level
| Idle |
| 30.4 / 30.4 / 30.4 dB(A) |
| Load |
| 32.3 / 35.2 dB(A) |
 | ||
30 dB silent 40 dB(A) audible 50 dB(A) loud |
||
min:  , med:  , max:  Audix TM1, Arta (15 cm distance) environment noise: 30.6 dB(A) | ||
Temperature
The Inspiron completed our stress test (Prime95 and FurMark running simultaneously for at least an hour) in the same way in both AC power mode and battery mode. At the beginning of the test the processor ran at 2.5 GHz, while the graphics core went about its task at 850 to 900 MHz. After about 5 minutes, the situation changed. The CPU throttled to 1.6 GHz and the GPU accelerated to 1000 MHz. The convertible laptop never heated to particularly high temperatures. During the stress test, we measured temperatures over the 40°C mark (104°F) in only three spots. These numbers were lower in everyday use.
(+) The maximum temperature on the upper side is 37.3 °C / 99 F, compared to the average of 35.3 °C / 96 F, ranging from 19.6 to 60 °C for the class Convertible.
(±) The bottom heats up to a maximum of 43.3 °C / 110 F, compared to the average of 36.8 °C / 98 F
(+) In idle usage, the average temperature for the upper side is 24.3 °C / 76 F, compared to the device average of 30.3 °C / 87 F.
(+) The palmrests and touchpad are cooler than skin temperature with a maximum of 25.5 °C / 77.9 F and are therefore cool to the touch.
(+) The average temperature of the palmrest area of similar devices was 28.1 °C / 82.6 F (+2.6 °C / 4.7 F).
Speakers
Dell Inspiron 15 5578-1777 2-in-1 audio analysis
(-) | not very loud speakers (67 dB)
Bass 100 - 315 Hz
(±) | reduced bass - on average 10.3% lower than median
(±) | linearity of bass is average (7.3% delta to prev. frequency)
Mids 400 - 2000 Hz
(±) | higher mids - on average 6.6% higher than median
(±) | linearity of mids is average (7.3% delta to prev. frequency)
Highs 2 - 16 kHz
(±) | higher highs - on average 5.5% higher than median
(±) | linearity of highs is average (12.7% delta to prev. frequency)
Overall 100 - 16.000 Hz
(±) | linearity of overall sound is average (19.6% difference to median)
Compared to same class
» 46% of all tested devices in this class were better, 6% similar, 48% worse
» The best had a delta of 6%, average was 21%, worst was 57%
Compared to all devices tested
» 46% of all tested devices were better, 7% similar, 47% worse
» The best had a delta of 4%, average was 25%, worst was 134%
Apple MacBook 12 (Early 2016) 1.1 GHz audio analysis
(+) | speakers can play relatively loud (83.6 dB)
Bass 100 - 315 Hz
(±) | reduced bass - on average 11.3% lower than median
(±) | linearity of bass is average (14.2% delta to prev. frequency)
Mids 400 - 2000 Hz
(+) | balanced mids - only 2.4% away from median
(+) | mids are linear (5.5% delta to prev. frequency)
Highs 2 - 16 kHz
(+) | balanced highs - only 2% away from median
(+) | highs are linear (4.5% delta to prev. frequency)
Overall 100 - 16.000 Hz
(+) | overall sound is linear (10.2% difference to median)
Compared to same class
» 6% of all tested devices in this class were better, 2% similar, 92% worse
» The best had a delta of 5%, average was 19%, worst was 53%
Compared to all devices tested
» 4% of all tested devices were better, 1% similar, 95% worse
» The best had a delta of 4%, average was 25%, worst was 134%
Frequency comparison (checkboxes are selectable/deselectable)
Power Consumption
While idling, we recorded a maximum energy consumption rate of 9.8 watts - a reasonable figure. During the stress test, the rate rose to 3.4 watts. When the CPU throttled after about 5 minutes, the number sank to 28.4 watts. The power supply is rated at 45 watts.
| Off / Standby | 0.25 / 0.35 Watt |
| Idle | 4.3 / 7.6 / 9.8 Watt |
| Load |
32.6 / 28.4 Watt |
   
| |
Key:
min: ,
med: ,
max: Metrahit Energy | |
Battery Life
Our WLAN test - designed to simulate normal, everyday use - uses a script to keep the system busy by regularly loading new websites. The "balanced" profile is active, the laptop's energy saving functions are deactivated, and the display brightness is set to about 150 cd/m². The Inspiron reached a run time of 6 hours and 34 minutes: a good 90 minutes longer than its structurally identical Skylake predecessor.
| Battery Runtime - WiFi Websurfing | |
| Dell Inspiron 15 5578-1777 2-in-1 | |
| HP Pavilion x360 15-bk102ng | |
| Lenovo Yoga 510-15ISK | |
| Dell Inspiron 15 5568 | |
Pros
Cons
Verdict
The Inspiron 15 5578 is a 15.6-inch convertible laptop of Dell's creation. Only its inner workings diverge from those of the previous model. The manufacturer now relies on a Kaby Lake processor, equipping its system with enough performance power to fearlessly face the coming years. The Inspiron does not irritate its users with a relentless fan, or an antiquated whizzing hard drive. In idle mode, the machine generally goes about its business in perfect silence; even under load the fan is not an overachiever. The computer also remains cool no matter the circumstance.
A fast solid-state disk enables the system to run with speed. It is possible to switch out the SSD, as the base plate is removable. The computer's battery life is certainly nothing to sneeze at. The touchscreen functions flawlessly and reacts instantly to input from your fingers or an active stylus. To test the latter, we prodded at and drew across the screen with a stylus manufactured by Hama - to our full satisfaction. Overall, we also deem the backlit keyboard a success.
In every relevant area, the Inspiron profits from the Kaby Lake upgrade. The computer's battery life has improved in no small measure, and the system has gained performance power.
The IPS display is pleasing to the eyes, with its good visibility from all angles and screen orientations, high contrast, and color representation that achieves an above average degree of accuracy. The display brightness is too low for outdoor use - sadly, users of this computer will be confined to the indoors. Not good: The device lacks a USB Type-C port. We expect at least one of these ports in a laptop on today's market.
A note regarding warranty: If you buy the Inspiron from the Dell website, the standard warranty length is one year. In Europe, purchasing the computer from another website (ex. notebooksbilliger.de) provides the buyer with a two-year warranty. In both cases the warranty can be extended - Dell offers a plethora of options here.
Dell Inspiron 15 5578-1777 2-in-1
- 01/18/2017 v6 (old)
Sascha Mölck
Price comparison
