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Dell XPS 15 9575 vs. HP Spectre x360 15 2018: Kaby Lake-G Showdown

One Kaby Lake-G Winner. We benchmark and compare the only two laptops in existence currently shipping with Kaby Lake-G processors. We were expecting overall results to be quite similar between them, but they couldn't have been any more different to our genuine surprise.

The Dell XPS 15 9575 and HP Spectre x360 15 2018 are unique in that they are the only 15-inch convertibles with Kaby Lake-G processors currently in the market. Both OEMs have carved themselves a small niche with these powerful but unpopular CPUs designed for multimedia and mainstream gaming.

As a consequence of carrying the same CPU with similar 2-in-1 form factors, the 15-inch Dell and HP convertibles have been in direct competition with one another ever since launch. To our surprise, the systems are more dissimilar than what their paper specifications would otherwise suggest. Our comparison below highlights the differences between them in terms of features, performance, noise, brightness, connectivity, and more.

We encourage users to check out our dedicated review pages below for more data and detailed analyses of each of the two models.


HP Spectre x360 15 2018Dell XPS 15 9575
CPUCore i7-8550U or Core i7-8705GCore i5-8305G or Core i7-8705G
GPUNvidia GeForce MX150 or AMD Radeon RX Vega M GL w/ 4 GB HBM2 VRAMAMD Radeon RX Vega M GL w/ 4 GB HBM2 VRAM
RAM2x SODIMM, 8 GB to 16 GB DDR4-2400Soldered, 8 GB or 16 GB DDR4-2400
Display4K UHD touchscreen (BOE0730)4K UHD touchscreen (Sharp SHP148E)
Storage1x M.2 2280 slot, Upgradeable1x M.2 2280 slot, Upgradeable
KeyboardMembrane-based, 2.2 mm travel Maglev, 0.7 mm travel
Touchpad12 x 6 cm10.5 x 8.0 cm
SpeakersBang & Olufsen stereo (2 W x 2)Stereo (1 W x 2)
CameraFHD IR, top of display720p IR, bottom of display
ConnectivitySee below See below
Weight2.1 kg2.0 kg
Dimensions359 x 250 x 19.3 mm354 x 235 x 16 mm
MSRPVariesVaries

 

HP Spectre x360 15 2018
HP Spectre x360 15 2018
Dell XPS 15 9575
Dell XPS 15 9575

Case

The Dell system is lighter, thinner, and smaller than the HP equivalent by several millimeters in each dimension. Users accustomed to handling an XPS 15 9550/9560/9570 will know exactly what to expect with the XPS 15 9575 as Dell has translated the design language almost perfectly for the 2-in-1 form factor. Both models show excellent build quality with minimal warping down the outer lid and keyboard base. We can't objectively rank one system better than the other in this regard.

We can, however, give the HP a small edge over the Dell. Its all-aluminum surfaces are much better at hiding fingerprints than the carbon fiber palm rests of the Dell and we believe this will help keep the HP system looking cleaner and newer over time. Otherwise, the Dell is preferable if portability and size are top concerns.

Thicker, heavier, and larger in all three dimensions
Thicker, heavier, and larger in all three dimensions
Hinges are slightly stronger than the Dell
Hinges are slightly stronger than the Dell
All-aluminum chassis is better at repelling fingerprints
All-aluminum chassis is better at repelling fingerprints
Power button w/ integrated fingerprint reader
Power button w/ integrated fingerprint reader
Webcam placement is along the bottom instead of the top
Webcam placement is along the bottom instead of the top
Same aluminum and carbon fiber makeup as the XPS 15 9560
Same aluminum and carbon fiber makeup as the XPS 15 9560
359 mm / 14.1 inch 250 mm / 9.84 inch 19.3 mm / 0.76 inch 2.1 kg4.72 lbs354 mm / 13.9 inch 235 mm / 9.25 inch 16 mm / 0.63 inch 2 kg4.41 lbs

Connectivity

HP has the clear advantage here as far as port selection is concerned. The full-size SD reader, HDMI-out, and USB Type-A are all absent on the XPS 15 9575. Even the volume rocker is present on the HP only. In contrast, Dell owners should be prepared to carry Type-C adapters wherever they go as the system offers almost nothing other than four USB Type-C ports.

It’s important to remember that the Dell system utilizes USB Type-C for charging whereas the HP relies on a proprietary AC adapter port. The more versatile Dell adapter can also be used to charge other USB Type-C devices including smartphones and tablets.

HP Spectre x360 15 2018
HP Spectre x360 15 2018
HP Spectre x360 15 2018
HP Spectre x360 15 2018
Dell XPS 15 9575
Dell XPS 15 9575
Dell XPS 15 9575
Dell XPS 15 9575
Ports and Connections

HP Spectre x360 15 2018 Dell XPS 15 9575
USB 1x USB 3.1 Type-A, 2x USB Type-C + Thunderbolt 3 4x USB Type-C (2x Thunderbolt 3)
Video-out 1x HDMI, mDP via USB Type-C mDP via USB Type-C
Audio 3.5 mm combo 3.5 mm combo
Other SD reader MicroSD reader
Storage Bays 1x M.2 2280 1x M.2 2280
SDCardreader Transfer Speed
average JPG Copy Test (av. of 3 runs)
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
178.4 MB/s ∼100%
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
138 MB/s ∼77%
maximum AS SSD Seq Read Test (1GB)
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
208.6 MB/s ∼100%
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
200.36 MB/s ∼96%
Networking
iperf3 Client (receive) TCP 1 m 4M x10
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
640 MBit/s ∼100%
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
634 MBit/s ∼99%
iperf3 Client (transmit) TCP 1 m 4M x10
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
521 MBit/s ∼100%
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
506 MBit/s ∼97%

Input Devices

The keyboards and trackpads couldn’t be more different between the HP and Dell. While the Spectre utilizes a more traditional membrane-based keyboard with a dedicated NumPad, the XPS 15 9575 opts for a one-of-a-kind MagLev keyboard with no NumPad. Key travel is over three times deeper on the HP as a result since the MagLev keys are designed to provide firm feedback without requiring deep key depth. 

A notable advantage for the XPS 15 9575 is that its MagLev keys promise excellent feedback consistency over time whereas the traditional keys on the HP may eventually wear down from heavy use. Otherwise, typing quality comes down to user preference as we don’t particularly find one set of keys to be objectively better than the other.

The roomier and squarer trackpad of the Dell is generally more comfortable to use for multi-touch inputs compared to the unique 2:1 aspect ratio of the HP trackpad. Regardless, the integrated trackpad mouse keys are about equally poor and spongy on both systems.

HP adds a full-size NumPad but gets a smaller 12 x 6 cm trackpad
HP adds a full-size NumPad but gets a smaller 12 x 6 cm trackpad
Dell omits the NumPad but gets a larger 10.5 x 8.0 cm trackpad
Dell omits the NumPad but gets a larger 10.5 x 8.0 cm trackpad
Standard chiclet keys with deep 2.2 mm key travel will feel more familiar to Windows users
Standard chiclet keys with deep 2.2 mm key travel will feel more familiar to Windows users
Special MagLev keys and its shallow 0.7 mm key travel are closer to a MacBook Pro 15 experience
Special MagLev keys and its shallow 0.7 mm key travel are closer to a MacBook Pro 15 experience

Display

On the surface, both competing models offer the same crisp Gorilla Glass-protected 4K UHD touchscreen with support for WACOM pen inputs. However, the devil is in the details once again because each manufacturer utilizes a different panel supplier than the other. The BOE0730 panel on the HP is dimmer, of lower contrast, and with a narrower color gamut than the Sharp SHP148E panel on the Dell. This ultimately means that the Dell is able to offer more accurate colors and deeper blacks that may appeal to heavy multimedia users and artists. In return, the HP system offers faster response times for less ghosting when gaming.

Users sensitive to onscreen flickering should note that both the HP and Dell systems exhibit very similar pulse-width modulation (PWM) frequencies. PWM on the HP, however, is present on all brightness levels except the maximum while PWM is only present on the Dell at a brightness setting of 25 percent or under. The Spectre has a higher chance of causing eyestrain after prolong use.

HP Spectre x360 15 2018
HP Spectre x360 15 2018
Dell XPS 15 9575
Dell XPS 15 9575
HP Spectre x360 15 subpixel array
HP Spectre x360 15 subpixel array
Dell XPS 15 9575 subpixel array
Dell XPS 15 9575 subpixel array
HP Spectre x360 15 2018
HP Spectre x360 15 2018
Dell XPS 15 9575
Dell XPS 15 9575
Spectre x360 15 PWM
Spectre x360 15 PWM
Spectre x360 15 black-white response times
Spectre x360 15 black-white response times
XPS 15 9575 PWM
XPS 15 9575 PWM
XPS 15 9575 black-white response times
XPS 15 9575 black-white response times
HP Spectre x360 15-ch000Dell XPS 15 9575 i7-8705G
Response Times
Response Time Grey 50% / Grey 80% *
36 (18, 18)
48.4 (23.2, 25.2)
Response Time Black / White *
23.6 (12, 11.6)
34.8 (19.2, 15.6)
PWM Frequency
943.4 (99)
1000 (25)
Screen
Brightness middle
349.5
488
Brightness
331
440
Brightness Distribution
90
81
Black Level *
0.29
0.3
Contrast
1205
1627
Colorchecker DeltaE2000 *
4.06
3.16
Colorchecker DeltaE2000 max. *
7.68
8.8
Colorchecker DeltaE2000 calibrated *
4.22
Greyscale DeltaE2000 *
4.4
3.3
Gamma
2.11 104%
2.178 101%
CCT
7422 88%
6811 95%
Color Space (Percent of AdobeRGB 1998)
56.5
71.7
Color Space (Percent of sRGB)
86.9
97.9
Total Average (Program / Settings)

* ... smaller is better

Spectre x360 15 2018 color profile
Spectre x360 15 2018 color profile
Dell XPS 15 9575 color profile
Dell XPS 15 9575 color profile

Performance

CPU Performance

Both models return very similar CineBench scores as one would expect since they use the same Core i7-8705G SoC. The Dell and HP score 732 and 746 points in CineBench R15 Multi-Thread, respectively, to represent a performance difference of less than 1 percent. Dig deeper, however, and differences begin to show.

Performance sustainability is superior on the Dell system when compared to the HP despite both performing similarly on a cold boot. By running CineBench R15 Multi-Thread in a loop, we can observe that the HP system experiences steeper declines in performance over time. The HP averages about 630 points after about ten loops compared to 680 points on the Dell.

See our dedicated pages on the Core i7-8705G for more technical information. For the sake of completion, we've also included the Intel Hades Canyon NUC and Core i5-8305G below.

HP Spectre x360 15 2018. The hard-to-reach M.2 drive is hidden underneath ribbons
HP Spectre x360 15 2018. The hard-to-reach M.2 drive is hidden underneath ribbons
Dell XPS 15 9575. Easily upgradeable SSD
Dell XPS 15 9575. Easily upgradeable SSD
0102030405060708090100110120130140150160170180190200210220230240250260270280290300310320330340350360370380390400410420430440450460470480490500510520530540550560570580590600610620630640650660670680690700710720730740Tooltip
Cinebench R15 CPU Multi 64 Bit (HP Spectre x360 15 Core i7-8705G). CPU performance is generally slower and less steady over time
0102030405060708090100110120130140150160170180190200210220230240250260270280290300310320330340350360370380390400410420430440450460470480490500510520530540550560570580590600610620630640650660670680690700710720730740750Tooltip
Cinebench R15 CPU Multi 64 Bit (Dell XPS 15 9575 Core i7-8705G). Throttling still occurs, but to a lesser degree than on the HP
Cinebench R15
CPU Single 64Bit (sort by value)
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
174 Points ∼80%
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
165 Points ∼76%
Dell XPS 15 9575 i5-8305G
Vega M GL / 870, 8305G, Toshiba XG5 KXG50ZNV256G
157 Points ∼72%
Intel Hades Canyon NUC8i7HVK
Vega M GH, 8809G, Intel Optane 120 GB SSDPEK1W120GA
178 Points ∼82%
HP Spectre x360 15-ch011nr
GeForce MX150, 8550U, SK hynix PC401 NVMe 500 GB
149 Points ∼68%
CPU Multi 64Bit (sort by value)
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
699 Points ∼16%
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
707 Points ∼16%
Dell XPS 15 9575 i5-8305G
Vega M GL / 870, 8305G, Toshiba XG5 KXG50ZNV256G
681 Points ∼16%
Intel Hades Canyon NUC8i7HVK
Vega M GH, 8809G, Intel Optane 120 GB SSDPEK1W120GA
864 Points ∼20%
HP Spectre x360 15-ch011nr
GeForce MX150, 8550U, SK hynix PC401 NVMe 500 GB
523 Points ∼12%
Cinebench R11.5
CPU Single 64Bit (sort by value)
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
1.97 Points ∼81%
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
1.89 Points ∼77%
Dell XPS 15 9575 i5-8305G
Vega M GL / 870, 8305G, Toshiba XG5 KXG50ZNV256G
1.79 Points ∼73%
Intel Hades Canyon NUC8i7HVK
Vega M GH, 8809G, Intel Optane 120 GB SSDPEK1W120GA
1.99 Points ∼82%
CPU Multi 64Bit (sort by value)
Dell XPS 15 9575 i7-8705G
Vega M GL / 870, 8705G, SK hynix PC401 NVMe 500 GB
7.65 Points ∼28%
HP Spectre x360 15-ch000
Vega M GL / 870, 8705G, Toshiba XG5-P KXG50PNV2T04
7.59 Points ∼28%
Dell XPS 15 9575 i5-8305G
Vega M GL / 870, 8305G, Toshiba XG5 KXG50ZNV256G
7.47 Points ∼28%
Intel Hades Canyon NUC8i7HVK
Vega M GH, 8809G, Intel Optane 120 GB SSDPEK1W120GA
9.41 Points ∼35%

GPU Performance

Raw GPU performance is consistently below that of our Dell counterpart by single-digit percentage points according to 3DMark benchmarks. Both the slower CPU and GPU clock rates of the HP when gaming are responsible for the slightly lower scores.

For the sake of completion, we’ve also included benchmark scores for the XPS 15 9575 Core i5-8305G, Intel Hades Canyon Core i7-8809G, and the HP Spectre x360 15 Core i7-8550U below. 

See our Radeon RX Vega M GL page for more technical information and benchmark comparisons.

3DMark
1920x1080 Fire Strike Combined
Intel Hades Canyon NUC8i7HVK
3210 Points ∼100%
Dell XPS 15 9575 i7-8705G
2282 Points ∼71%
Dell XPS 15 9575 i5-8305G
2269 Points ∼71%
HP Spectre x360 15-ch000
2132 Points ∼66%
HP Spectre x360 15-ch011nr
1212 Points ∼38%
1920x1080 Fire Strike Physics
Intel Hades Canyon NUC8i7HVK
12168 Points ∼100%
Dell XPS 15 9575 i7-8705G
11246 Points ∼92%
Dell XPS 15 9575 i5-8305G
10476 Points ∼86%
HP Spectre x360 15-ch000
10091 Points ∼83%
HP Spectre x360 15-ch011nr
9124 Points ∼75%
1920x1080 Fire Strike Graphics
Intel Hades Canyon NUC8i7HVK
10248 Points ∼100%
Dell XPS 15 9575 i5-8305G
7355 Points ∼72%
Dell XPS 15 9575 i7-8705G
7348 Points ∼72%
HP Spectre x360 15-ch000
7059 Points ∼69%
HP Spectre x360 15-ch011nr
3622 Points ∼35%
1920x1080 Fire Strike Score
Intel Hades Canyon NUC8i7HVK
8506 Points ∼100%
Dell XPS 15 9575 i7-8705G
6280 Points ∼74%
Dell XPS 15 9575 i5-8305G
6235 Points ∼73%
HP Spectre x360 15-ch000
5951 Points ∼70%
HP Spectre x360 15-ch011nr
3267 Points ∼38%
3DMark 11
1280x720 Performance Combined
Intel Hades Canyon NUC8i7HVK
10391 Points ∼100%
Dell XPS 15 9575 i7-8705G
8633 Points ∼83%
HP Spectre x360 15-ch000
8405 Points ∼81%
Dell XPS 15 9575 i5-8305G
7788 Points ∼75%
HP Spectre x360 15-ch011nr
4296 Points ∼41%
1280x720 Performance Physics
Intel Hades Canyon NUC8i7HVK
11010 Points ∼100%
Dell XPS 15 9575 i7-8705G
9742 Points ∼88%
HP Spectre x360 15-ch000
8907 Points ∼81%
Dell XPS 15 9575 i5-8305G
8182 Points ∼74%
HP Spectre x360 15-ch011nr
8038 Points ∼73%
1280x720 Performance GPU
Intel Hades Canyon NUC8i7HVK
14302 Points ∼100%
Dell XPS 15 9575 i7-8705G
10118 Points ∼71%
Dell XPS 15 9575 i5-8305G
9862 Points ∼69%
HP Spectre x360 15-ch000
9632 Points ∼67%
HP Spectre x360 15-ch011nr
4708 Points ∼33%
Cinebench R15 - OpenGL 64Bit
Intel Hades Canyon NUC8i7HVK
151.85 fps ∼100%
Dell XPS 15 9575 i7-8705G
125.49 fps ∼83%
HP Spectre x360 15-ch000
124.1 fps ∼82%
Dell XPS 15 9575 i5-8305G
117.23 fps ∼77%
HP Spectre x360 15-ch011nr
104.31 fps ∼69%
Rise of the Tomb Raider - 1920x1080 High Preset AA:FX AF:4x (sort by value)
Dell XPS 15 9575 i7-8705G
42.4 fps ∼22%
HP Spectre x360 15-ch000
35 fps ∼19%
Dell XPS 15 9575 i5-8305G
40.6 fps ∼21%
Intel Hades Canyon NUC8i7HVK
53.9 fps ∼29%
HP Spectre x360 15-ch011nr
23 fps ∼12%
BioShock Infinite - 1920x1080 Ultra Preset, DX11 (DDOF) (sort by value)
Dell XPS 15 9575 i7-8705G
52.5 fps ∼20%
HP Spectre x360 15-ch000
51.7 fps ∼19%
Dell XPS 15 9575 i5-8305G
51.7 fps ∼19%
Intel Hades Canyon NUC8i7HVK
81.4 fps ∼31%
HP Spectre x360 15-ch011nr
35.2 fps ∼13%

Stress Test

We subject the system to extreme processing stress to test for stability and behavior when under high loads. When running Prime95, the CPU in the Spectre stabilizes in the 2.0 to 2.7 GHz range compared to 3.1 to 3.5 GHz on the XPS 15 9575. The notable difference mirrors our CineBench loop test from above where the Dell system would consistently outscore the HP over longer periods.

Running Witcher 3 is more representative of real-world gaming conditions. The GPU in the Spectre can be observed stabilizing at just 400 to 535 MHz after about 15 minutes compared to the steady 1011 MHz on the Dell. The steep frame rate drops above reflect the very low GPU clock rates on the HP. Furthermore, core temperatures are notably higher on the HP than on the Dell by about over 10 degrees C. The HP is not only slower, but it also runs warmer as well. Its performance is extremely disappointing for any gamer or video editor interested in the Kaby Lake-G Spectre.

Spectre x360 15 2018 (Prime95 stress)
Spectre x360 15 2018 (Prime95 stress)
Spectre x360 15 2018 (Prime95+FurMark stress)
Spectre x360 15 2018 (Prime95+FurMark stress)
Spectre x360 15 2018 (Witcher 3 stress)
Spectre x360 15 2018 (Witcher 3 stress)
Dell XPS 15 9575 (Prime95 stress)
Dell XPS 15 9575 (Prime95 stress)
Dell XPS 15 9575 (Prime95+FurMark stress)
Dell XPS 15 9575 (Prime95+FurMark stress)
Dell XPS 15 9575 (Witcher 3 stress)
Dell XPS 15 9575 (Witcher 3 stress)
01234567891011121314151617181920212223242526272829303132333435363738394041Tooltip
The Witcher 3 high (HP Spectre x360 15 Core i7-8705G). Frame rates are normal at first, but they begin to dip after about 15 minutes of gaming
0123456789101112131415161718192021222324252627282930313233343536373839404142434445464748Tooltip
The Witcher 3 high (Dell XPS 15 9575 Core i7-8705G). Stable frame rates from beginning to end
CPU and GPU Clock Rates Under Stress

HP Spectre x360 15 2018 Dell XPS 15 9575
Processor Core i7-8705G Core i7-8705G
Rated GPU Core Clock (MHz) 931 931
Stable GPU Core Clock on Witcher 3 (MHz) 400 - 535 1011
Rated CPU Core Clock (GHz) 3.1 3.1
Stable CPU Core Clock on Prime95 (GHz) 2.0 - 2.7 3.1 - 3.5
Average CPU temperature on Witcher 3 75 C 58 C
Average GPU temperature on Witcher 3 66 C 57 C
HP Spectre x360 15 2018
HP Spectre x360 15 2018
Dell XPS 15 9575
Dell XPS 15 9575

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Emissions and Energy

System Noise and Temperature

The symmetrical cooling system of the HP is preferable for gaming because the commonly used WASD and NumPad keys remain relatively cool. In contrast, the left half of the Dell will always be noticeably warmer than the right simply because of how the heat pipes are arranged underneath. The inevitable temperature difference between the left and right hand palms is less than ideal when typing or gaming.

As for their hot spots, both systems are quite similar in absolute temperature at about 45 C and 50 C on the front and back, respectively, despite the XPS 15 9575 being thinner and lighter. Dell is able to achieve this by utilizing special GORE insulators not found on notebooks outside of the XPS family.

Dell has the advantage yet again when it comes to fan noise. The XPS 15 9575 is more likely to remain silent when emailing or word processing whereas the fans on the Spectre are always active no matter the load. Gaming is generally louder on the HP despite its under-performing GPU.

Spectre x360 15 2018 top (idle)
Spectre x360 15 2018 top (idle)
Dell XPS 15 9575 top (idle)
Dell XPS 15 9575 top (idle)
Spectre x360 15 2018 bottom (idle)
Spectre x360 15 2018 bottom (idle)
Dell XPS 15 9575 bottom (idle)
Dell XPS 15 9575 bottom (idle)
Spectre x360 15 2018 top (maximum load)
Spectre x360 15 2018 top (maximum load)
Dell XPS 15 9575 top (maximum load)
Dell XPS 15 9575 top (maximum load)
Spectre x360 15 2018 bottom (maximum load)
Spectre x360 15 2018 bottom (maximum load)
Dell XPS 15 9575 bottom (maximum load)
Dell XPS 15 9575 bottom (maximum load)
HP Spectre x360 15-ch000HP Spectre x360 15-ch011nrDell XPS 15 9575 i7-8705GDell XPS 15 9575 i5-8305G
Noise
off / environment *
28.1
28.6
28.2
27.8
Idle Minimum *
30.8
29.2
28.2
27.8
Idle Average *
30.9
29.2
28.2
27.8
Idle Maximum *
30.9
29.2
28.2
27.8
Load Average *
31.8
29.2
29
35
Witcher 3 ultra *
48.1
38.4
44.7
44.2
Load Maximum *
44.2
45.7
47.4
44.2

* ... smaller is better

Power Consumption

Idling on desktop will draw anywhere between 11 W and 19 W on the HP compared to just 6 W and 14 W on the Dell. Our HP unit exhibits spikes in power consumption when idling to suggest that there is background activity responsible for the slightly higher power consumption.

When subjected to medium or extreme loads, both systems show similar power consumption levels. Running Witcher 3 demands about 85 W from each system even though performance is lower on the HP.

Prime95 activated at 20s mark on HP. Note that consumption is highest for the first few seconds before falling
Prime95 activated at 20s mark on HP. Note that consumption is highest for the first few seconds before falling
Prime95 activated at 20s mark on Dell. The system is able to maintain steadier clock rates and consumption compared to the HP
Prime95 activated at 20s mark on Dell. The system is able to maintain steadier clock rates and consumption compared to the HP
Prime95+FurMark activated at 20s mark on HP. Consumption is more unsteady compared to the Dell to suggest more throttling
Prime95+FurMark activated at 20s mark on HP. Consumption is more unsteady compared to the Dell to suggest more throttling
Prime95+FurMark activated at 20s mark on Dell. Consumption spikes at the start of the test before quickly dropping and stabilizing
Prime95+FurMark activated at 20s mark on Dell. Consumption spikes at the start of the test before quickly dropping and stabilizing
HP Spectre x360 15-ch000HP Spectre x360 15-ch011nrDell XPS 15 9575 i7-8705G
Power Consumption
Idle Minimum *
11.7
5.3
6.2
Idle Average *
16.8
9.8
12.9
Idle Maximum *
18.9
12.6
13.6
Load Average *
82.3
73
76.1
Load Maximum *
94.9
80
99.4
Witcher 3 ultra *
87.2
67.6
84.3

* ... smaller is better

Battery Life

The HP has a 12 percent larger battery capacity than the Dell for a total of 84 W. Nonetheless, the equivalent Dell configuration is still able to outlast the HP by about an hour when subjected to similar WLAN conditions. Kaby Lake-G appears to be less power efficient than Kaby Lake-R during low loads as the Kaby Lake-R version of the Spectre x360 15 can run for almost twice as long.

Charging from empty is faster on the HP at about 2 hours compared to 2.5 hours on the XPS 15 9575.

HP Spectre x360 15-ch000
84 Wh
HP Spectre x360 15-ch011nr
84 Wh
Dell XPS 15 9575 i7-8705G
75 Wh
Dell XPS 15 9575 i5-8305G
75 Wh
Battery Runtime
Reader / Idle
540
927
673
663
WiFi v1.3
344
625
420
564
Load
66
135
63
78

Verdict

The strong Spectre x360 15 chassis puts up a very good fight against the XPS 15 9575. Unfortunately for HP, the XPS 15 9575 has it beaten in nearly every other category including performance
The strong Spectre x360 15 chassis puts up a very good fight against the XPS 15 9575. Unfortunately for HP, the XPS 15 9575 has it beaten in nearly every other category including performance

Normally for our "Versus" pages, it's difficult to crown one model over another because each system would have a long list of advantages that may cater better to a specific type of user. In this case, however, the Dell XPS 15 9575 is the superior Kaby Lake-G laptop by a wide margin over the HP Spectre x360 15. It's measurably quieter, cooler, lighter, thinner, brighter, and longer-lasting with deeper colors while suffering from far fewer throttling issues when under load. Power users who want the most that the Core i7-8705G SoC can offer should avoid the HP solution until the OEM can address the throttling problems, if ever.

To HP's credit, the Kaby Lake-G Spectre still offers a few notable advantages over Dell. Its more extensive range of integrated ports means owners won't have to rely on pricey adapters and its display response times are faster for less ghosting when gaming. Its internal speakers are louder and the dedicated NumPad is a boon for data entry. Unfortunately, the cons outweigh the short list of pros. The wider port options mean a larger chassis and the reduced ghosting means little when the system inevitably throttles whilst gaming. Its larger battery capacity is nothing but dead weight when even the smaller battery of the XPS 15 9575 is able to outlast it.

The best iteration of the Spectre x360 15 is still the Kaby Lake-R SKU with the more traditional Core i7-8550U CPU and GeForce MX150 graphics. For the best Kaby Lake-G experience on a laptop, look no further than the XPS 15 9575.

 

HP Spectre x360 15 2018Dell XPS 15 9575
+ More ports
+ Less prone to fingerprints
+ Louder speakers
+ Faster display response times
+ Dedicated NumPad
+ Better webcam positioning
+ Lighter, thinner, smaller
+ Brighter display
+ Wider color gamut
+ Easier serviceability
+ Longer battery life
+ Quieter fans
+ Cooler core temperatures
+ Steadier performance; no major throttling issues
+ Fingerprint-enabled Power button
+ Versatile USB Type-C charger
- Heavier, thicker, larger
- M.2 SSD slot more difficult to reach
- More acute throttling issues
- Louder fans
- Larger battery, but shorter battery life
- Pulse-width modulation on almost all brightness levels
- Dimmer display backlight
- Narrower color gamut
- Proprietary AC adapter
- Carbon fiber surfaces accumulate grease more easily
- More ghosting
- No integrated HDMI, USB Type-A, or full-size SD reader
- No NumPad
- Warmer WASD keys when gaming
- Slightly slower charging

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> Notebook / Laptop Reviews and News > Reviews > Dell XPS 15 9575 vs. HP Spectre x360 15 2018: Kaby Lake-G Showdown
Allen Ngo, 2018-08-28 (Update: 2018-09- 8)
Allen Ngo
Allen Ngo - US Editor in Chief
After graduating with a B.S. in environmental hydrodynamics from the University of California, I studied reactor physics to become licensed by the U.S. NRC to operate nuclear reactors. There's a striking level of appreciation you gain for everyday consumer electronics after working with modern nuclear reactivity systems astonishingly powered by computers from the 80s. When I'm not managing day-to-day activities and US review articles on Notebookcheck, you can catch me following the eSports scene and the latest gaming news.