Notebookcheck

Asus ZenBook 13 UX331UN (i7-8550U, MX150) Laptop Review

Benjamin Herzig (translated by Martin Jungowski), 01/11/2018

Portable all-rounder. Ultrabooks like the Dell XPS 13 are selling like hotcakes and every OEM wants a piece of the pie. Asus' candidate of choice is the ZenBook UX331UN, a high-quality subnotebook with a dedicated GPU. Read our extensive review to find out why it deserves a recommendation.

Not that long ago, the dominant and best-selling laptops were equipped with 15.6-inch displays. However, the ultrabook revolution that started in 2011 put the focus on smaller 13.3-inch devices. Asus, one of the ultrabook pioneers, has been part of that ultrabook revolution with its ZenBook series since the early days.

Today’s review unit is the ZenBook 13 UX331UN. Featuring a 13.3-inch display in a very thin metal case, an eighth-generation Intel Core CPU (Kaby Lake-Refresh), and an Nvidia GeForce MX150 GPU, the ZenBook is one of the strongest and most powerful contestants in this segment. Unfortunately for Asus, it is surrounded by more than worthy competitors like the Dell XPS 13, the HP Envy 13, the IdeaPad 320s-13IKBR, or the Swift 3 SF314-52G.

Our review unit was equipped with 16 GB of RAM and a 512 GB SSD. This particular configuration sells for 1400 Euros (~$1716) in Germany. US prices are not yet available.

Asus ZenBook 13 UX331UN (ZenBook 13 Series)
Graphics adapter
NVIDIA GeForce MX150 (Laptop GT 1030) - 2048 MB, Core: 1700 MHz, Memory: 1252 MHz, 382.84, Optimus
Memory
16384 MB 
, DDR3L, soldered
Display
13.3 inch 16:9, 1920 x 1080 pixel 166 PPI, B133HAN04.9, IPS LED, glossy: no
Mainboard
Intel Kaby Lake-U iHDCP 2.2 Premium PCH
Storage
SanDisk SD8SN8U512G1002, 512 GB 
, M.2 2280, 428 GB free
Soundcard
Intel Kaby Lake-U/Y PCH - High Definition Audio
Connections
3 USB 3.0 / 3.1 Gen1, 1 HDMI, Audio Connections: audio combo jack, Card Reader: MicroSD, 1 Fingerprint Reader
Networking
Intel Dual Band Wireless-AC 8265 (a/b/g/n/ac), Bluetooth 4.2
Size
height x width x depth (in mm): 13.9 x 310 x 216 ( = 0.55 x 12.2 x 8.5 in)
Battery
50 Wh Lithium-Polymer
Operating System
Microsoft Windows 10 Home 64 Bit
Camera
Webcam: 0.3 MP
Additional features
Speakers: stereo speakers, Keyboard: 6-row chiclet, Keyboard Light: yes, sleeve, display cloth, Netflix, Asus Live Update, Microsoft Office Trial, 24 Months Warranty
Weight
1.145 kg ( = 40.39 oz / 2.52 pounds), Power Supply: 198 g ( = 6.98 oz / 0.44 pounds)
Price
1199 Euro

 

Case

Asus ZenBook 13 UX331UN
Asus ZenBook 13 UX331UN

ZenBooks have a very high recognition value thanks to their brushed metal display lid with its concentric circles engraved into it. Other than that, the grayish case is everything but an eye-catcher and resembles a typical modern ultrabook. From a mere visual point of view, the blue model would certainly be more appealing. The display bezels are a bit wider than on many of its competitors; an aspect Asus should definitely consider addressing for the next iteration.

As mentioned before the entire case save for the display frame is made of metal, and overall build quality is excellent. Consequently, the base is very stiff and rigid despite its thickness of just 13.9 mm. Unfortunately, the display is much more susceptible to torsional forces and flexes quite easily. Selective force around the edges is no problem for the case but the closer you get to the center the more it flexes. Thus, the keyboard bends somewhat when typing fiercely.

The single hinge design’s maximum opening angle is 135 °, and the lid can be easily opened one-handed. On the downside this also means that the hinges are not firm enough to prevent display wobble entirely.

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Reducing thickness and weight must have been one of Asus’ top priorities when designing the new ZenBook, and it shows. At only 13.9 mm it is ever so slightly thinner than the HP Envy 13 and a full millimeter thinner than the Dell XPS 13. In addition, at only 1.1 kg it is the lightest ultrabook in this test group but is also the largest of all the 13.3-inch contestants.

Size Comparison

Connectivity

Connectivity options are adequate. Unfortunately, the ZenBook lacks support for Thunderbolt 3. In addition, Asus has failed to make the most out of USB-C by requiring an extra power port for charging the device instead of supporting charging via USB-C. To add insult to injury the USB-C port also lacks support for DisplayPort Alternate mode, meaning that it does not carry a video signal and cannot be used to connect to external displays.

Left: power, HDMI, USB 3.0 Type-A, USB 3.1 Gen 1 Type-C
Left: power, HDMI, USB 3.0 Type-A, USB 3.1 Gen 1 Type-C
Right: USB 3.0 Type-A, audio combo jack, MicroSD
Right: USB 3.0 Type-A, audio combo jack, MicroSD

SD Card Reader

Sometime in 2016, OEMs started omitting the SD card reader on notebooks more and more frequently. Today, compact notebooks and ultrabooks with SD card readers have become a rare sight, and unfortunately Asus has decided to follow the trend and installed a MicroSD instead of a full-sized SD card reader.

When benchmarked with our MicroSD reference card, a Toshiba Exceria Pro M501, it managed to transfer at a mediocre 80 MB/s.

SDCardreader Transfer Speed
average JPG Copy Test (av. of 3 runs)
Dell XPS 13 i7-8550U
159 MB/s ∼100% +119%
Lenovo IdeaPad 320S-13IKB
(Toshiba Exceria Pro M501)
78.1 MB/s ∼49% +7%
Asus ZenBook 13 UX331UN
(Toshiba Exceria Pro M501)
72.7 MB/s ∼46%
HP Envy 13-ad006ng
(Toshiba Exceria Pro SDXC 64 GB UHS-II)
72 MB/s ∼45% -1%
Acer Swift 3 SF314-52G-89SL
(Toshiba Exceria Pro SDXC 64 GB UHS-II)
22.8 MB/s ∼14% -69%
maximum AS SSD Seq Read Test (1GB)
Dell XPS 13 i7-8550U
190.59 MB/s ∼100% +131%
Lenovo IdeaPad 320S-13IKB
(Toshiba Exceria Pro M501)
84.9 MB/s ∼45% +3%
Asus ZenBook 13 UX331UN
(Toshiba Exceria Pro M501)
82.6 MB/s ∼43%
HP Envy 13-ad006ng
(Toshiba Exceria Pro SDXC 64 GB UHS-II)
80 MB/s ∼42% -3%
Acer Swift 3 SF314-52G-89SL
(Toshiba Exceria Pro SDXC 64 GB UHS-II)
24.9 MB/s ∼13% -70%

Communication

Intel’s Wireless 8265 has become the de-facto standard for Kaby Lake and Kaby Lake-R based notebooks. The 2x2 AC Wi-Fi modem performed as expected, both in benchmarks and everyday use.

Networking
iperf3 Client (receive) TCP 1 m 4M x10
Dell XPS 13 i7-8550U
Killer Wireless-n/a/ac 1535 Wireless Network Adapter
618 MBit/s ∼100% +2%
Asus ZenBook 13 UX331UN
Intel Dual Band Wireless-AC 8265
603 MBit/s ∼98%
HP Envy 13-ad006ng
Intel Dual Band Wireless-AC 7265
547 MBit/s ∼89% -9%
Lenovo IdeaPad 320S-13IKB
Intel Dual Band Wireless-AC 3165
326 MBit/s ∼53% -46%
Acer Swift 3 SF314-52G-89SL
Intel Dual Band Wireless-AC 7265
243 MBit/s ∼39% -60%
iperf3 Client (transmit) TCP 1 m 4M x10
HP Envy 13-ad006ng
Intel Dual Band Wireless-AC 7265
682 MBit/s ∼100% +32%
Acer Swift 3 SF314-52G-89SL
Intel Dual Band Wireless-AC 7265
670 MBit/s ∼98% +30%
Dell XPS 13 i7-8550U
Killer Wireless-n/a/ac 1535 Wireless Network Adapter
538 MBit/s ∼79% +4%
Asus ZenBook 13 UX331UN
Intel Dual Band Wireless-AC 8265
515 MBit/s ∼76%
Lenovo IdeaPad 320S-13IKB
Intel Dual Band Wireless-AC 3165
295 MBit/s ∼43% -43%

Security

Once upon a time, fingerprint-readers were only found on business notebooks but in the last few years, they have slowly but surely trickled down into the consumer space. The ZenBook features a touch fingerprint-reader that requires the finger to be placed on top of it instead of swiping across it. It worked as expected and allowed for a very fast login process.

Fingerprint-reader
Fingerprint-reader

Accessories

The ZenBook includes actually useful accessories in the box. In addition to a microfiber cleaning cloth for the display Asus also includes a matching sleeve for the UX331UN.

Maintenance

Ten T5 Torx screws have to be removed in order to get access to the ZenBook’s internal hardware. After that, the notebook started to come apart at the front but the bottom plate remained firmly attached to the base unit at the rear close to the hinge. We suspect plastic latches hold the bottom cover in place but were unable to locate and undo these with a spudger tool. In order to prevent damage to our review unit we decided to call it quits and left the case unopened.

With the bottom cover removed one should have access to various components, such as the battery, the SSD, or the fan. RAM is not upgradeable since it has been soldered onto the motherboard. Thus, defective RAM will require a motherboard replacement.

Warranty

Asus offers its ZenBook lineup with a two-year pickup & return limited warranty in Europe by default, but only a one-year carry-in limited warranty in the United States. Pickup and return means that Asus is going to pick the item up and ship it back to you once it has been fully repaired. As such, it beats the carry-in service that is most commonly offered as part of the default warranty package.

Input Devices

Keyboard

The ZenBook 13’s six-row keyboard features a four-stage backlight and a full-size layout. Other than the power button, which is located above the backspace key in the upper right corner, we haven’t had any issues with the keyboard layout at all. Keep in mind though that the Page Up/Down, Home and End keys can only be accessed via Fn key combination.

Unfortunately, the typing experience was rather poor. Key travel is short and feedback is very mushy, which means the feeling when typing is pretty awkward. Granted, there are much worse keyboards out there but that doesn’t make the ZenBook’s keyboard any better.

Touchpad

Fortunately, the touchpad was much better than the keyboard. It was very accurate and fast thanks to Microsoft’s Precision technology and drivers. Multitouch gestures were detected reliably and were spot-on every time.

The hardware itself was very decent as well. The ClickPad’s integrated buttons are very firm yet pleasantly quiet. The touchpad’s glass surface is very smooth, and all things considered we were very satisfied with the touchpad.

Input devices
Input devices

Display

AUO B133HAN04.9 subpixel geometry
AUO B133HAN04.9 subpixel geometry
Minor backlight-bleeding
Minor backlight-bleeding

The matte 16:9 FHD IPS display (1920x1080) is the only display currently offered for the UX331, and neither higher resolution displays nor touchscreens are available.

Our review unit was equipped with an AUO B113HAN04.9 panel. According to Panelook, this particular panel should offer up to 300 nits brightness. At 321 nits on average and a maximum of 338 nits, our review unit was even brighter than that. In our test group, the ZenBook’s display was the third brightest after the two XPS notebooks.

Brightness distribution was very decent (90%) and we found no evidence of PWM-flickering whatsoever. Unfortunately, there was some minor background-bleeding.

303
cd/m²
329
cd/m²
322
cd/m²
313
cd/m²
338
cd/m²
330
cd/m²
307
cd/m²
324
cd/m²
325
cd/m²
Distribution of brightness
X-Rite i1Pro 2
Maximum: 338 cd/m² Average: 321.2 cd/m² Minimum: 18.6 cd/m²
Brightness Distribution: 90 %
Center on Battery: 335 cd/m²
Contrast: 966:1 (Black: 0.35 cd/m²)
ΔE Color 4.2 | 0.8-23.34 Ø6.5
ΔE Greyscale 3.9 | 0.64-98 Ø6.7
93.1% sRGB (Argyll) 60.4% AdobeRGB 1998 (Argyll)
Gamma: 2.43
Asus ZenBook 13 UX331UN
B133HAN04.9, , 1920x1080, 13.3
Dell XPS 13 i7-8550U
ID: Sharp SHP144A, Name: LQ133Z1, , 3200x1800, 13.3
HP Envy 13-ad006ng
BOE070E, , 1920x1080, 13.3
Lenovo IdeaPad 320S-13IKB
InfoVision M133NWF4R0, , 1920x1080, 13.3
Acer Swift 3 SF314-52G-89SL
AU Optronics B140HAN02.1, , 1920x1080, 14
Dell XPS 13 9360 FHD i7 Iris
SHP1449, , 1920x1080, 13.3
Response Times
-23%
-59%
-78%
-32%
-40%
Response Time Grey 50% / Grey 80% *
22.4 (10.8, 11.6)
35.6 (18.4, 17.2)
-59%
48 (23, 25)
-114%
56.8 (27.6, 29.2)
-154%
41 (19, 22)
-83%
41.2 (22.8, 18.4)
-84%
Response Time Black / White *
31.2 (17.2, 14)
27.2 (16, 11.2)
13%
32 (17, 15)
-3%
31.6 (17.6, 14)
-1%
25 (15, 10)
20%
30 (17.6, 12.4)
4%
PWM Frequency
19690 (100)
1000 (90)
198.4 (99)
19530 (80)
Screen
-2%
-8%
20%
-22%
13%
Brightness
321
357
11%
264
-18%
304
-5%
217
-32%
418
30%
Brightness Distribution
90
83
-8%
83
-8%
88
-2%
88
-2%
85
-6%
Black Level *
0.35
0.33
6%
0.23
34%
0.25
29%
0.27
23%
0.2
43%
Contrast
966
1170
21%
1222
27%
1320
37%
863
-11%
2305
139%
Colorchecker DeltaE2000 *
4.2
4.2
-0%
4.83
-15%
1.8
57%
5.85
-39%
5.4
-29%
Greyscale DeltaE2000 *
3.9
5.7
-46%
6.63
-70%
2.5
36%
4.87
-25%
5.4
-38%
Gamma
2.43 99%
2.28 105%
1.85 130%
2.11 114%
2.47 97%
2.15 112%
CCT
7144 91%
7336 89%
6794 96%
6588 99%
6908 94%
7258 90%
Color Space (Percent of AdobeRGB 1998)
60.4
59
-2%
56
-7%
61.8
2%
34
-44%
48.6
-20%
Color Space (Percent of sRGB)
93.1
92.2
-1%
86
-8%
97.3
5%
54
-42%
76.9
-17%
Total Average (Program / Settings)
-13% / -7%
-34% / -18%
-29% / 0%
-27% / -24%
-14% / 2%

* ... smaller is better

Colors
Colors
Saturation
Saturation
Grayscale
Grayscale
Colors (calibrated)
Colors (calibrated)
Saturation (calibrated)
Saturation (calibrated)
Grayscale (calibrated)
Grayscale (calibrated)

A black level of 0.35 nits results in a contrast ratio of 966:1 - decent, but not exceptional. Most competitors offer a higher contrast ratio. Subjectively, the display was very nice to look at. Colors pop and blacks are dark enough to not have any grayish implications.

Out of the box, the panel had a minor blue tint - fairly uncommon for an IPS display. A blue tint is more common on TN panels while IPS panels more often than not exhibit a green tint. Regardless of tint, display calibration did help and managed to improve overall image quality significantly. As always, the resulting ICC profile can be found for download in the box above.

Color-space coverage is quite important for overall color quality, and the AUO panel did not disappoint. 93% sRGB is practically a guarantee for high color accuracy. Thus, despite missing complete sRGB coverage by a few percent, the display is most certainly not going to stand in the way of any (semi-) professional photo-editing ambitions.

sRGB: 93.1%
sRGB: 93.1%
AdobeRGB: 60.4%
AdobeRGB: 60.4%
Outdoors (overcast)
Outdoors (overcast)

Outdoor usability depends mostly on two factors: brightness and reflectivity. Given the matte display and a brightness of over 320 nits it is safe to say that the ZenBook is more than just usable outdoors. Its outdoor ambitions will only be thwarted by direct sunlight; indirect bright sunlight caused no issues at all.

Display Response Times

Display response times show how fast the screen is able to change from one color to the next. Slow response times can lead to afterimages and can cause moving objects to appear blurry (ghosting). Gamers of fast-paced 3D titles should pay special attention to fast response times.
       Response Time Black to White
31.2 ms ... rise ↗ and fall ↘ combined↗ 17.2 ms rise
↘ 14 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. » 79 % of all devices are better.
This means that the measured response time is worse than the average of all tested devices (26.5 ms).
       Response Time 50% Grey to 80% Grey
22.4 ms ... rise ↗ and fall ↘ combined↗ 10.8 ms rise
↘ 11.6 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 0.9 (minimum) to 636 (maximum) ms. » 7 % of all devices are better.
This means that the measured response time is better than the average of all tested devices (42.3 ms).

Screen Flickering / PWM (Pulse-Width Modulation)

To dim the screen, some notebooks will simply cycle the backlight on and off in rapid succession - a method called Pulse Width Modulation (PWM) . This cycling frequency should ideally be undetectable to the human eye. If said frequency is too low, users with sensitive eyes may experience strain or headaches or even notice the flickering altogether.
Screen flickering / PWM not detected

In comparison: 54 % of all tested devices do not use PWM to dim the display. If PWM was detected, an average of 8615 (minimum: 43 - maximum: 142900) Hz was measured.

Most IPS panels offer excellent viewing angles, and the ZenBook delivered as expected. A slight drop in brightness and contrast ratio can be observed from very acute and extreme angles, but it was negligible overall.

AUO B133HAN04.9 viewing angles
AUO B133HAN04.9 viewing angles

Performance

At the time of writing, Asus offers seven different ZenBook 13 UX331 models in Europe ranging from 989 to 1,399 Euros (~$1212 to ~$1715). All SKUs are equipped with the same 13.3-inch FHD IPS display and a GeForce MX150.

Where the respective models differ is in CPU performance (Core i5-8250U or Core i7-8550U), SSD storage capacity (256 or 512 GB), and RAM. All SKUs except for the 1,399 Euros (~$1715) expensive top model are equipped with 8 GB DDR3L memory; the latter features 16 GB thereof instead. Given that the RAM is soldered onto the motherboard it’s better to be safe than sorry.

HWiNFO
HWiNFO
CPU-Z
CPU-Z
CPU-Z Caches
CPU-Z Caches
CPU-Z Mainboard
CPU-Z Mainboard
CPU-Z Memory
CPU-Z Memory
GPU-Z Intel UHD 620
GPU-Z Intel UHD 620
LatencyMon
LatencyMon
 

Processor

The quad-core Core i7-8550U is a member of Intel’s brand-new Kaby Lake-Refresh family. Given its 15 W TDP it is considered a ULV (ultra-low voltage) CPU. In single-threaded applications, it can turbo boost up to 4 GHz. Additional information and benchmarks can be found in our CPU benchmark table.

These new power-efficient quad-core CPUs are much more reliant on cooling and power consumption. More often than not maximum turbo boost speeds cannot be held for more than just a few seconds. This does not surprise us at all: Multi-core performance at high clock speeds would require a much higher thermal envelope of 45 W instead, which would in turn defeat the purpose of a power-efficient 15 W CPU for small and thin notebooks such as this. Proper cooling-provided OEMs can opt to enlarge the thermal envelope to allow for higher clock speeds and ultimately higher performance in sustained load scenarios.

In this particular case, the CPU is allowed to use up to 32 W at the beginning and runs with up to 3.2 GHz accordingly. After reaching a temperature threshold of 90 °C, all cores clock down to 2.6 GHz and power consumption is lowered to 22 W. Running the Cinebench R15 multithread benchmark just once yields a score of 616 points. Running the same benchmark in a 30-minute loop produces scores as low as 394 points. The individual results vary wildly, and occasionally they shoot up to 530 points. The two culprits for this inconsistent behavior are the temperature and the power limit defined by Asus, or more precisely the overstrained cooling system. Power usage under sustained load drops further to first 25 W, then 18 W, and eventually bottoms out at 15 W. On average, the ZenBook’s Cinebench R15 multithread score was 456 points.

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Cinebench R15 CPU Multi 64 Bit

Short-term performance bursts are ideal for the ZenBook, where it bests the entire competition. Sustained load, however, is much more consistent on other notebooks, such as the Dell XPS 13: It averaged 560 points in our Cinebench R15 multithread loop.

CPU performance is limited when running on battery and the ZenBook only managed to score up to 530 points in Cinebench R15 on battery.

Cinebench R15
CPU Single 64Bit
Acer Swift 3 SF314-52G-89SL
Intel Core i7-8550U
167 Points ∼100% +3%
Dell XPS 13 i7-8550U
Intel Core i7-8550U
167 Points ∼100% +3%
Asus ZenBook 13 UX331UN
Intel Core i7-8550U
162 Points ∼97%
HP Envy 13-ad006ng
Intel Core i7-7500U
145 Points ∼87% -10%
Lenovo IdeaPad 320S-13IKB
Intel Core i5-8250U
132 Points ∼79% -19%
CPU Multi 64Bit
Asus ZenBook 13 UX331UN
Intel Core i7-8550U
623 Points ∼100%
Dell XPS 13 i7-8550U
Intel Core i7-8550U
603 Points ∼97% -3%
Acer Swift 3 SF314-52G-89SL
Intel Core i7-8550U
550 Points ∼88% -12%
Lenovo IdeaPad 320S-13IKB
Intel Core i5-8250U
516 Points ∼83% -17%
HP Envy 13-ad006ng
Intel Core i7-7500U
353 Points ∼57% -43%
Cinebench R15 OpenGL 64Bit
93.71 fps
Cinebench R15 Ref. Match 64Bit
99.6 %
Cinebench R15 CPU Multi 64Bit
623 Points
Cinebench R15 CPU Single 64Bit
162 Points
Help

System Performance

When compared with modern tablets or smartphones, many PCs seem to wake up from standby much slower despite their more powerful and faster hardware. The ZenBook is one of the faster PCs in this regard and wakes up almost instantaneously. In everyday use, its powerful CPU, SSD, and plentiful RAM availability help immensely to improve overall system performance. The ZenBook’s PCMark benchmark scores are a perfect reflection of this.

PCMark 8
Work Score Accelerated v2
Asus ZenBook 13 UX331UN
GeForce MX150, 8550U, SanDisk SD8SN8U512G1002
5037 Points ∼100%
HP Envy 13-ad006ng
GeForce MX150, 7500U, Toshiba NVMe THNSN5256GPUK
4900 Points ∼97% -3%
Lenovo IdeaPad 320S-13IKB
GeForce MX150, 8250U, Samsung PM961 NVMe MZVLW512HMJP
4826 Points ∼96% -4%
Dell XPS 13 i7-8550U
UHD Graphics 620, 8550U, Toshiba XG5 KXG50ZNV256G
4436 Points ∼88% -12%
Home Score Accelerated v2
Acer Swift 3 SF314-52G-89SL
GeForce MX150, 8550U, Intel SSD 600p SSDPEKKW512G7
3968 Points ∼100% +2%
Asus ZenBook 13 UX331UN
GeForce MX150, 8550U, SanDisk SD8SN8U512G1002
3899 Points ∼98%
Lenovo IdeaPad 320S-13IKB
GeForce MX150, 8250U, Samsung PM961 NVMe MZVLW512HMJP
3796 Points ∼96% -3%
HP Envy 13-ad006ng
GeForce MX150, 7500U, Toshiba NVMe THNSN5256GPUK
3773 Points ∼95% -3%
Dell XPS 13 i7-8550U
UHD Graphics 620, 8550U, Toshiba XG5 KXG50ZNV256G
3432 Points ∼86% -12%
PCMark 10 - Score
Acer Swift 3 SF314-52G-89SL
GeForce MX150, 8550U, Intel SSD 600p SSDPEKKW512G7
3805 Points ∼100% +24%
HP Envy 13-ad006ng
GeForce MX150, 7500U, Toshiba NVMe THNSN5256GPUK
3282 Points ∼86% +7%
Lenovo IdeaPad 320S-13IKB
GeForce MX150, 8250U, Samsung PM961 NVMe MZVLW512HMJP
3191 Points ∼84% +4%
Asus ZenBook 13 UX331UN
GeForce MX150, 8550U, SanDisk SD8SN8U512G1002
3071 Points ∼81%
PCMark 8 Home Score Accelerated v2
3899 points
PCMark 8 Work Score Accelerated v2
5037 points
Help

Storage Devices

The 512 GB SSD installed in our review unit was a SanDisk SD8SN8U512G1002. This particular model is not a PCIe NVMe SSD but is a slower SATA III SSD instead. It was much faster than regular spinning hard disk drives but could not keep up with a modern NVMe SSD. Since all of its competitors in this test group were equipped with NVMe SSDs, the ZenBook came in last in the storage benchmarks. In everyday use, the slower SSD became particularly obvious when copying large amounts of data.

Asus ZenBook 13 UX331UN
SanDisk SD8SN8U512G1002
Dell XPS 13 i7-8550U
Toshiba XG5 KXG50ZNV256G
HP Envy 13-ad006ng
Toshiba NVMe THNSN5256GPUK
Lenovo IdeaPad 320S-13IKB
Samsung PM961 NVMe MZVLW512HMJP
Acer Swift 3 SF314-52G-89SL
Intel SSD 600p SSDPEKKW512G7
AS SSD
58%
38%
258%
108%
Access Time Write *
0.09
0.051
43%
0.034
62%
0.029
68%
0.031
66%
Access Time Read *
0.143
0.102
29%
0.233
-63%
0.063
56%
0.07
51%
4K-64 Write
174.87
325.07
86%
66.74
-62%
1236.27
607%
521.15
198%
4K-64 Read
362.83
423.65
17%
616.15
70%
1226.47
238%
506.15
40%
4K Write
49.58
101.66
105%
89.44
80%
127.64
157%
117.53
137%
4K Read
25.47
28.17
11%
31.22
23%
50.28
97%
29.55
16%
Seq Write
283.31
249.23
-12%
247.83
-13%
1478.65
422%
567.11
100%
Seq Read
448.23
1277.09
185%
1368.98
205%
2309.62
415%
1609.25
259%

* ... smaller is better

SanDisk SD8SN8U512G1002
Sequential Read: 430.6 MB/s
Sequential Write: 424.1 MB/s
512K Read: 275 MB/s
512K Write: 369.8 MB/s
4K Read: 28.04 MB/s
4K Write: 53.47 MB/s
4K QD32 Read: 322.9 MB/s
4K QD32 Write: 211.9 MB/s

Graphics Card

GPU-Z Nvidia GeForce MX150
GPU-Z Nvidia GeForce MX150

Our review unit’s mobile mid-range GeForce MX150 GPU is based on Nvidia’s GeForce GT 1030 desktop chip and, unlike many other mobile GPUs, it does not have a fixed TDP an OEM has to adhere to. In other words: actual performance depends on individual implementation.

Let’s take for example the Acer Swift 3 SF314-52G. In this particular notebook, Acer has managed to fully utilize the MX150’s potential. Accordingly, it was the fastest MX150-equipped notebook in our test group, and it was up to 24% faster than the ZenBook. At the other end of the MX150 spectrum are devices such as the Lenovo IdeaPad 320s-13IKBR, whose MX150 only barely managed to outperform the much older GeForce 940MX.

On battery, some benchmark results (3DMark Cloudgate, Cinebench R15 OpenGL) were lower than on mains. We suspect the throttled CPU to be responsible for these drops in performance since the GPU-intensive 3DMark Firestrike benchmark yielded identical results on battery and mains. Unlike the CPU, the GPU is thus not artificially throttled when running on battery.

3DMark 11 - 1280x720 Performance GPU
Acer Swift 3 SF314-52G-89SL
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-8550U
4690 Points ∼100% +31%
Asus ZenBook 13 UX331UN
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-8550U
3581 Points ∼76%
HP Envy 13-ad006ng
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-7500U
3459 Points ∼74% -3%
Lenovo IdeaPad 320S-13IKB
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i5-8250U
2796 Points ∼60% -22%
Dell XPS 13 i7-8550U
Intel UHD Graphics 620, Intel Core i7-8550U
1810 Points ∼39% -49%
3DMark
1920x1080 Fire Strike Graphics
Asus ZenBook 13 UX331UN
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-8550U
2903 Points ∼100%
HP Envy 13-ad006ng
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-7500U
2841 Points ∼98% -2%
Lenovo IdeaPad 320S-13IKB
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i5-8250U
2324 Points ∼80% -20%
Dell XPS 13 i7-8550U
Intel UHD Graphics 620, Intel Core i7-8550U
1158 Points ∼40% -60%
1280x720 Cloud Gate Standard Graphics
Asus ZenBook 13 UX331UN
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-8550U
18572 Points ∼100%
HP Envy 13-ad006ng
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i7-7500U
17750 Points ∼96% -4%
Lenovo IdeaPad 320S-13IKB
NVIDIA GeForce MX150 (Laptop GT 1030), Intel Core i5-8250U
16227 Points ∼87% -13%
Dell XPS 13 i7-8550U
Intel UHD Graphics 620, Intel Core i7-8550U
9511 Points ∼51% -49%
3DMark 11 Performance
3811 points
3DMark Cloud Gate Standard Score
9861 points
3DMark Fire Strike Score
2563 points
Help

Gaming Performance

Despite the fact that the ZenBook certainly is no gaming notebook many modern games will run at reduced resolutions and medium quality thanks to its GeForce MX150 GPU. For example, The Witcher 3 ran smoothly with 32 FPS at 1366x768 and medium details. Sustained load (The Witcher 3 Ultra) did not result in GPU throttling and thus lower frame rates.

01234567891011Tooltip
The Witcher 3 ultra

If you are in the market for a compact and portable ultrabook capable of at least moderate gaming, then an MX150-equipped notebook is the best choice. It may not be the fastest gaming GPU out there but it most certainly beats Intel’s integrated UHD 620. Ryzen Mobile might bring a breath of fresh air thanks to its integrated Vega GPU but so far, our one and only Ryzen review unit - the HP Envy x360 15 - turned out to be rather disappointing in this regard.

BioShock Infinite - 1920x1080 Ultra Preset, DX11 (DDOF)
Acer Swift 3 SF314-52G-89SL
GeForce MX150, 8550U, Intel SSD 600p SSDPEKKW512G7
34 fps ∼100% +14%
Asus ZenBook 13 UX331UN
GeForce MX150, 8550U, SanDisk SD8SN8U512G1002
29.91 fps ∼88%
HP Envy 13-ad006ng
GeForce MX150, 7500U, Toshiba NVMe THNSN5256GPUK
29.72 fps ∼87% -1%
HP Envy x360 15m-bq121dx
Vega 8, 2500U, HGST Travelstar 7K1000 HTS721010A9E630
20 fps ∼59% -33%
Dell XPS 13 i7-8550U
UHD Graphics 620, 8550U, Toshiba XG5 KXG50ZNV256G
10 fps ∼29% -67%
The Witcher 3 - 1366x768 Medium Graphics & Postprocessing
Asus ZenBook 13 UX331UN
GeForce MX150, 8550U, SanDisk SD8SN8U512G1002
32.44 fps ∼100%
HP Envy 13-ad006ng
GeForce MX150, 7500U, Toshiba NVMe THNSN5256GPUK
27.64 fps ∼85% -15%
Lenovo IdeaPad 320S-13IKB
GeForce MX150, 8250U, Samsung PM961 NVMe MZVLW512HMJP
24.44 fps ∼75% -25%
low med. high ultra
BioShock Infinite (2013) 101.0377.9368.4829.91fps
The Witcher 3 (2015) 55.1432.4414.18.9fps
Doom (2016) 58.8349.4321.89fps

Emissions

System Noise

When idle, the ZenBook’s fan is completely off - not uncommon for 15 W ultrabooks. On the other hand, with more than 40 dB(A) it does get quite loud under load. In fact, it was the loudest notebook in our test group, both under load and while running games. Fortunately, the fan noise frequency is rather low, which means it was loud but not obnoxious or annoying just yet.

We found no evidence of coil whine on the ZenBook.

Noise Level

Idle
29.6 / 29.6 / 29.6 dB(A)
Load
41.7 / 43.5 dB(A)
 
 
 
30 dB
silent
40 dB(A)
audible
50 dB(A)
loud
 
min: dark, med: mid, max: light   Audix TM1, Arta (15 cm distance)   environment noise: 29.6 dB(A)
dB(A) 0102030405060708090Deep BassMiddle BassHigh BassLower RangeMidsHigher MidsLower HighsMid HighsUpper HighsSuper Highs203229.82928.82528.529.628.8293129.828.528.528.44028.328.630.428.55032.132.431.432.86328.127.727.927.48026.526.327.227.410027.82928.529.712526.124.624.225.216024.424.323.224.720024.923.822.425.125025.423.521.825.731524.823.920.324.840023.822.618.823.750024.423.118.424.763024.222.818.124.280027.426.117.627.5100030.83017.131.4125030.829.316.930.5160029.327.616.928.9200036.234.516.736250035.433.516.735.3315030.929.516.931400031.730.116.931.5500032.330.117.132.4630029.92717.430.3800025.523.317.725.7100002220.518221250019.118.717.919.31600018.418.41818.5SPL43.541.829.643.4N4.13.51.34.1median 26.1Asus ZenBook 13 UX331UNmedian 24.6median 17.9median 25.7Delta2.93.21.93.333.231.632.633.831.133.232.333.329.132.330.532.335.736.834.435.635.135.732.130.232.728.430.632.132.63331.832.729.132.627.828.828.330.226.927.826.727.227.527.326.926.725.925.827.726.625.925.925.725.425.524.824.325.723.424.324.424.223.623.423.5232323.22323.522.322.922.42221.622.322.421.421.221.720.822.421.320.720.520.320.421.321.320.42019.519.621.321.92120.418.918.521.923.823.521.918.818.323.82625.623.618.2182622.221.920.117.717.822.224.823.921.817.717.324.825.724.522.217.617.825.727.826.824.217.717.827.826.926.223.417.817.826.929.328.325.318.118.229.325.825.220.918.318.325.822.32219.318.418.222.319.519.418.818.618.619.519.119.118.918.718.719.118.918.818.818.818.818.919.1191919.11919.137.336.634.330.630.537.32.62.421.51.42.6median 23.4HP Envy 13-ad006ngmedian 23median 21.8median 18.8median 18.6median 23.42.72.31.91.81.82.7hearing rangehide median Fan Noise

Temperature

Stress test (Prime95+Furmark) after around 10 minutes
Stress test (Prime95+Furmark) after around 10 minutes
Stress test (Prime95+Furmark) after around 1 hour
Stress test (Prime95+Furmark) after around 1 hour

A very thin case mixed with a quad-core CPU and a dedicated GPU usually add up to a significant amount of heat. Not so with the ZenBook: Despite its powerful hardware and thin case it remained relatively cool. Running The Witcher 3, the hottest spot we found on the device’s surface was just 40 °C - warm, but not yet uncomfortable or dangerous.

During our stress test, running Prime95 and Furmark simultaneously, we ended up with a severely throttled notebook. Maximum CPU turbo boost could only be maintained for a few seconds, after which it dropped to 2.7 GHz. Another 30 seconds later, it dropped even further to the CPU's base clock speed of 1.8 GHz and bottomed out two minutes later at just 0.8 GHz, where it remained until the end of the test run. The GPU was throttled from the very start and ran at just 700 MHz. The culprit for this behavior was the under-designed cooling system that simply could not keep up with extreme loads such as this.

Running 3DMark 11 immediately after the stress test yielded the expected result. Thus, extreme load has no negative impact on everyday performance.

Max. Load
 37.1 °C34.3 °C40.9 °C 
 32.7 °C32.9 °C36.2 °C 
 26.1 °C25.7 °C28.1 °C 
Maximum: 40.9 °C
Average: 32.7 °C
38.1 °C37.6 °C34.8 °C
33.6 °C33.5 °C30 °C
28.7 °C27.6 °C27.1 °C
Maximum: 38.1 °C
Average: 32.3 °C
Power Supply (max.)  39.8 °C | Room Temperature 20 °C | Voltcraft IR-900

Speakers

Over the years we have learned not to expect too much from notebooks speakers. Fortunately, the ZenBook 13 UX331UN breaks the ranks and performs admirably in this regard.

Its stereo speakers are located at the bottom and are made by Harman Kardon, according to an imprint on the palm rest. More often than not these name-brand stickers aren’t worth the paper they are printed on but in this particular case, Asus has actually managed to surprise us with more than decent sound quality despite the ZenBook’s ultra-thin case. The only thing lacking is bass, but it most certainly beats the Dell XPS 13 in terms of sound quality by a long shot.

As expected, the built-in 3.5-mm audio jack worked flawlessly.

dB(A) 0102030405060708090Deep BassMiddle BassHigh BassLower RangeMidsHigher MidsLower HighsMid HighsUpper HighsSuper Highs2032.732.32530.531.63128.328.94029.432.15034.232.46329.331.68026.534.110030.541.912525.149.716025.849.120024.753.625023.654.431522.559.740021.15950019.662.963018.868.380018.571.2100017.771.3125017.372.8160017.672.1200017.473.5250017.470.7315017.571.640001868.3500017.970.3630018.369.9800018.670.81000018.769.41250018.868.31600018.864.8SPL30.582.8N1.556.1median 18.7Asus ZenBook 13 UX331UNmedian 68.3Delta2.3639.439.636.436.933.833.733.834.732.837.332.33832.642.630.648.33051.328.853.629.754.728.157.927.759.426.255.825.656.525.259.124.663.924.164.32466.523.766.823.765.623.66023.656.723.458.423.46423.257.323.265.623.362.123.252.723.243.336.275.22.736.6median 24Dell XPS 13 i7-8550Umedian 58.41.64.4hearing rangehide median Pink Noise
Asus ZenBook 13 UX331UN audio analysis

(+) | speakers can play relatively loud (82.8 dB)
Bass 100 - 315 Hz
(-) | nearly no bass - on average 16.9% lower than median
(±) | linearity of bass is average (9% delta to prev. frequency)
Mids 400 - 2000 Hz
(+) | balanced mids - only 4.3% away from median
(+) | mids are linear (4.2% delta to prev. frequency)
Highs 2 - 16 kHz
(+) | balanced highs - only 1.8% away from median
(+) | highs are linear (3.4% delta to prev. frequency)
Overall 100 - 16.000 Hz
(+) | overall sound is linear (13.3% difference to median)
Compared to same class
» 18% of all tested devices in this class were better, 3% similar, 80% worse
» The best had a delta of 9%, average was 20%, worst was 47%
Compared to all devices tested
» 10% of all tested devices were better, 3% similar, 87% worse
» The best had a delta of 3%, average was 21%, worst was 53%

Dell XPS 13 i7-8550U audio analysis

(-) | not very loud speakers (66.8 dB)
Bass 100 - 315 Hz
(+) | good bass - only 4.5% away from median
(±) | linearity of bass is average (8.2% delta to prev. frequency)
Mids 400 - 2000 Hz
(±) | higher mids - on average 5% higher than median
(+) | mids are linear (5.8% delta to prev. frequency)
Highs 2 - 16 kHz
(+) | balanced highs - only 3% away from median
(±) | linearity of highs is average (14.5% delta to prev. frequency)
Overall 100 - 16.000 Hz
(+) | overall sound is linear (13.8% difference to median)
Compared to same class
» 20% of all tested devices in this class were better, 3% similar, 77% worse
» The best had a delta of 9%, average was 20%, worst was 47%
Compared to all devices tested
» 12% of all tested devices were better, 4% similar, 85% worse
» The best had a delta of 3%, average was 21%, worst was 53%

Frequency diagram (checkboxes selectable/deselectable!)

Energy Management

Power Consumption

Asus has done an amazing job optimizing the ZenBook for low power consumption: It was the most efficient contestant in our test group under all load scenarios save for maximum load and maximum idle consumption, where the Dell XPS 13 managed to beat the ZenBook by a mere 0.2 watts.

The 65 W power supply is amply dimensioned.

Power Consumption
Off / Standbydarklight 0.33 / 0.9 Watt
Idledarkmidlight 2.7 / 5.3 / 6.2 Watt
Load midlight 37.6 / 60.1 Watt
 color bar
Key: min: dark, med: mid, max: light        Metrahit Energy
Asus ZenBook 13 UX331UN
8550U, GeForce MX150, SanDisk SD8SN8U512G1002, IPS LED, 1920x1080, 13.3
Dell XPS 13 i7-8550U
8550U, UHD Graphics 620, Toshiba XG5 KXG50ZNV256G, IGZO IPS, 3200x1800, 13.3
HP Envy 13-ad006ng
7500U, GeForce MX150, Toshiba NVMe THNSN5256GPUK, IPS LED, 1920x1080, 13.3
Lenovo IdeaPad 320S-13IKB
8250U, GeForce MX150, Samsung PM961 NVMe MZVLW512HMJP, IPS LED, 1920x1080, 13.3
Acer Swift 3 SF314-52G-89SL
8550U, GeForce MX150, Intel SSD 600p SSDPEKKW512G7, IPS, 1920x1080, 14
Power Consumption
-8%
-9%
-17%
-36%
Idle Minimum *
2.7
4.1
-52%
2.8
-4%
3.4
-26%
4.4
-63%
Idle Average *
5.3
5.8
-9%
5.8
-9%
6.1
-15%
6.6
-25%
Idle Maximum *
6.2
6
3%
7.7
-24%
7.7
-24%
9.2
-48%
Load Average *
37.6
42.5
-13%
48
-28%
44.2
-18%
61
-62%
Load Maximum *
60.1
41.4
31%
48
20%
60.3
-0%
50
17%
Witcher 3 ultra *
35
37.6
40

* ... smaller is better

Battery Life

The ZenBook’s 50 Wh battery is mediocre for an ultra-portable ultrabook. The HP Envy 13’s battery is about the same capacity while the Dell XPS 13 boasts a 60 Wh battery instead.

Nevertheless, battery life was excellent thanks to the notebook’s very low power consumption. In our real-world Wi-Fi test, the ZenBook outran the HP Envy 13 by 16% but was in turn outperformed by the XPS 13.

The battery supports quick charge and can be charged up to 60% in 49 minutes according to Asus. We were able to reproduce this easily and can thus positively confirm this claim. However, we also have to add that charging slowed down significantly past 80% charge level. A complete cycle from near empty to 100% takes almost 2 hours.

Charging time: 115 minutes
Charging time: 115 minutes
Battery life (idle): 1,321 minutes
Battery life (idle): 1,321 minutes
Battery life (load): 120 minutes
Battery life (load): 120 minutes
Battery life (Big Buck Bunny): 576 minutes
Battery life (Big Buck Bunny): 576 minutes
Battery life (Wi-Fi): 504 minutes
Battery life (Wi-Fi): 504 minutes
Battery Runtime
Idle (without WLAN, min brightness)
22h 01min
WiFi Surfing v1.3
8h 24min
Big Buck Bunny H.264 1080p
9h 36min
Load (maximum brightness)
2h 00min
Asus ZenBook 13 UX331UN
8550U, GeForce MX150, 50 Wh
Dell XPS 13 i7-8550U
8550U, UHD Graphics 620, 60 Wh
HP Envy 13-ad006ng
7500U, GeForce MX150, 51 Wh
Lenovo IdeaPad 320S-13IKB
8250U, GeForce MX150, 36 Wh
Acer Swift 3 SF314-52G-89SL
8550U, GeForce MX150, 48 Wh
Battery Runtime
7%
-11%
-39%
-8%
Reader / Idle
1321
1108
-16%
1198
-9%
736
-44%
H.264
576
476
-17%
346
-40%
WiFi v1.3
504
589
17%
425
-16%
344
-32%
465
-8%
Load
120
143
19%
118
-2%
73
-39%

Verdict

Pros

+ high-quality metal case
+ nearly perfect touchpad
+ IPS display with decent color-space coverage
+ high display brightness + matte display = great outdoor usability
+ dedicated GPU supports modern games
+ powerful speakers
+ case remains relatively cool
+ decent battery life

Cons

- inconsistent CPU performance
- CPU throttled on battery
- poor keyboard
- system noise under load
- no Thunderbolt 3
- no NVMe SSD
Asus ZenBook 13 UX331UN. Review unit courtesy of Asus.
Asus ZenBook 13 UX331UN. Review unit courtesy of Asus.

All things considered, we were quite happy with the ZenBook 13 UX331UN. It features a high-quality display and surprisingly decent speakers, which are the prime ingredients of a multimedia notebook that can be used outdoors thanks to its impressive maximum display brightness. In addition, the combination of CPU and GPU is powerful enough to run games smoothly at reduced resolutions and details. As such, the ZenBook is a textbook example of a true all-rounder. It is thin and light, features a high-quality case, a very good touchpad, and it remains cool most of the time. In addition, battery life is excellent despite the run-of-the-mill 50 Wh battery.

Combined, those are some impressive pros. Unfortunately, the ZenBook is not quite perfect just yet and has a number of flaws. The keyboard is only so-so, the cooling system is not powerful enough, CPU performance is very inconsistent, and the processor tends to throttle too early and too often (which we were able to confirm in Cinebench R15 and our stress test scenario). Not only that, the CPU is also significantly slower when running on battery. And let’s not forget the level of noise the ZenBook emits under load and when running games. In fact, it is borderline annoying for the more sensitive user. Last but not least, the built-in SATA III SSD, the lack of Thunderbolt 3, and the severely limited USB-C port (no support for DisplayPort) are also noteworthy disadvantages.

Compelling: By and large Asus has managed to hit the jackpot with the ZenBook 13 UX331UN in all the right places.

The pros unambiguously outweigh the cons, which is why the ZenBook 13 UX331UN deserves a recommendation. When looking for a portable notebook with a discreet GPU, it is most certainly a marvelous alternative to the Dell XPS 13.

Asus ZenBook 13 UX331UN - 01/05/2018 v6
Benjamin Herzig

Chassis
85 /  98 → 87%
Keyboard
83%
Pointing Device
94%
Connectivity
45 / 80 → 56%
Weight
73 / 78 → 89%
Battery
91%
Display
88%
Games Performance
70 / 68 → 100%
Application Performance
82 / 87 → 94%
Temperature
92 / 91 → 100%
Noise
90%
Audio
82 / 91 → 90%
Camera
39 / 85 → 46%
Average
78%
88%
Subnotebook - Weighted Average

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> Notebook / Laptop Reviews and News > Reviews > Asus ZenBook 13 UX331UN (i7-8550U, MX150) Laptop Review
Benjamin Herzig, 2018-01-11 (Update: 2018-01-15)