Dell XPS 15 9575 (i7-8705G, Vega M GL, 4K UHD) Convertible Review

Keyboard & Touchpad

As mentioned before, the MagLev keyboard will take some time to become accustomed to because it feels very different from the usual membrane-based keyboards found on most Windows laptops. Travel is extremely shallow (0.7 mm) to give an experience more akin to a MacBook that users will either love or hate. We can, however, appreciate the fact that feedback is uniform and very consistent between each main key. We wish the Function keys and Arrow keys could have been larger as the super-short travel pairs poorly with their small sizes.

The included WACOM Premium Active Pen (PN579X) is 15 cm in length with 4096 levels of pressure sensitivity and a 240 Hz report rate as defined by the AES 2.0 standard. The top button and two side buttons are used to launch applications and pair with the system. Unfortunately, the side buttons have weak feedback when pressed compared to the Microsoft Surface Pen and they could have benefited from a firmer feel. Unlike on the older Dell Active Stylus Pen, the newer Premium Active Pen has no pen hook near the top for clamping onto clothing or paperwork. Instead, the stylus relies on a magnet to stick onto objects and along the edge of the XPS system.

There appears to be no replacement pen tips at the time of writing.

AdobeRGB color space is smaller than on the 4K UHD panel for the XPS 15 9560 (72 percent vs. 88 percent). Despite double-checking our findings, Dell's only response is that the 4K UHD panel for the XPS 15 9575 promises 100 percent AdobeRGB coverage. Graphics artists may want to look elsewhere because of the questionable color coverage of the XPS 15 convertible.

The strange color behavior only continues with our X-Rite spectrophotometer analyses. Colors become notably more inaccurate the higher the saturation level despite having full sRGB coverage. Our automatic calibration attempts strangely do not improve upon this whereas our same procedure on other notebooks typically result in more accurate displays. In fact, setting the panel to sRGB mode through PremierColor creates a very imbalanced grayscale at the 90 percent saturation level as shown by our CalMAN results below. We're not sure why this is occurring on the 4K UHD panel and not the FHD panel, but more tuning will be necessary between PremierColor settings and Windows color profiles.

Outdoor visibility is good when under shade and merely average when under direct sunlight. The wide viewing angles and 360-degree hinges help in reducing as much glare as possible, but glare is still inevitable on the super-glossy panel. Certain 15-inch notebooks like the Samsung NP900X5N or even the MacBook Pro 15 are equipped with brighter backlighting for a superior experience than the Dell when outdoors.

The Core i7-8705G is within a few percentage points from the Core i5-8305G in both single- and multi-threaded workloads according to CineBench. The delta is so insignificant compared to the price difference between the Kaby Lake-G Core i5 and Core i7 SKUs that most users will not even notice the minuscule benefits of the Core i7 CPU. With that said, its performance is still comparable to the Core i7-7700HQ CPU as found on the XPS 15 9560 and most Kaby Lake gaming notebooks of 2017. The Core i7-8750H currently shipping on the latest XPS 15 9570 is about 50 percent faster than our XPS convertible in multi-threaded workloads while the i7-8809G can be almost 25 percent faster.

Running CineBench R15 Multi-Thread in a loop results in an initial high score of 749 points before stabilizing in the 680 range to represent a performance drop of about 9 percent. In comparison, the i5-8305G SKU is able to achieve an initial high score of 710 points before stabilizing at about 670 to represent a drop of almost 6 percent. Though these dips are relatively minor, neither of these processors can maintain maximum Turbo Boost for more than just 30 seconds or so at best.

See our dedicated page on the Core i7-8705G CPU for more technical information and benchmarks.

PCMark benchmarks have been scoring all our Kaby Lake-G systems quite highly. Both of our XPS 15 9575 configurations are within single-digit percentages from powerful systems like the Asus Zenbook Pro UX550 and even the latest Gigabyte Aero 15X v8.

We experienced no major hardware or software issues during our time with the unit aside from the color issues above.

In Intel systems, the same integrated HD Graphics 620 GPU can be found on a wide range of U-class CPUs from the Core i3-7100U to the Core i7-7600U. Actual GPU performance, however, is still very similar between these systems. The same can be said for the AMD Radeon RX Vega M GL GPU in the Core i5-8305G and Core i7-8705G. 3DMark results show that both of the Dell SKUs are nearly identical in raw graphics performance to the point where any benefits in gaming should be unnoticeable. As our Stress Test section will show, the Vega M GL GPU runs at the same 1011 MHz clock rate between the two i5 and i7 CPUs.

Raw graphics power is between the GTX 1050 and GTX 1050 Ti and comparable to the GTX 965M. Thus, gamers can expect similar performance levels to the XPS 15 9560. Some titles, however, may run much slower on the AMD GPU due to poorer optimization. See our dedicated page on the Radeon RX Vega M GL here for more technical information and benchmarks.

We stress the laptop to identify for any potential throttling or stability issues. When running Prime95 to stress the CPU, clock speeds can be observed running at 3.7 GHz for the first 20 seconds or so before dropping and stabilizing in the 3.1 to 3.5 GHz range. The higher initial clock speeds mirror our CineBench loop test from above where the high initial score of 746 points can only be attainable on a cold run. When compared to the XPS 15 9575 Core i5-8305G SKU, the Core i7-8705G runs warmer and at higher clock rates when at 100 percent capacity. Running Prime95 and FurMark simultaneously to stress the system will throttle both the CPU and GPU in order to maintain a stable core temperature of 64 C.

Running Witcher 3 is more representative of the types of loads gamers will experience. The CPU and GPU can be observed operating at stable 3.8 GHz and 1011 MHz clock rates, respectively, compared to 3.4 GHz and 1011 MHz on the i5-8305G in the less expensive XPS 15 9575 SKU. Core temperature is slightly cooler as well likely due in part to differences in ambient temperature. Despite the oddity, core temperatures are still significantly cooler than the GTX 1050 GPU in the ZenBook Flip 15 and just a few degrees warmer than the GTX 1050 in the thicker 17.3-inch Asus ROG Strix GL703VD.

Running on battery power will throttle GPU performance while CPU performance does not change. A 3DMark 11 run on batteries returns Physics and Graphics scores of 9762 and 5660 points, respectively, compared to 9742 and 10118 points when on mains.

Our first XPS 15 9575 review unit shipped with a faulty AC adapter and we were unable to provide our usual power consumption measurements as a result. Fortunately, our second XPS unit includes an operable AC adapter. It's worth noting that the adapter is rated for 130 W even though the industry specification for USB Type-C charging is limited to 100 W.

Idling on desktop will draw between 6 W and 14 W depending on the screen brightness and Power Profile settings. The results are very similar to the Asus ZenBook Flip 15 while also being significantly more power efficient than the XPS 15 9560 across the board. Gaming loads will demand about 85 W compared to 105 W on the XPS 15 9560 (w/ GTX 1050) even though raw GPU power is 20 percent faster on the XPS 15 9575. In short, the XPS convertible is both faster and more efficient than what the XPS 15 9560 series can offer. Notebooks with the GTX 1050 Ti may consume more power when gaming, but the overall differences in performance-per-Watt between these systems are more marginal than we were expecting.

What about the 130 W power delivery? Dell says it designed the USB Type-C connector in the XPS 15 2-in-1 to be uncapped for up to 130 W. To test this, we stressed the notebook to 100 percent activity with Prime95 and FurMark running simultaneously. Our graph below shows that power consumption spikes to almost 140 W in the first couple of seconds before quickly dropping to stabilize at around 88 W. Thus, while the system can indeed draw over 100 W, it is unsustainable. This thankfully has no impact on the actual performance of the system as 100 W appears to be more than sufficient in practice. The extra 30 W from the adapter is likely overhead to ensure stability.