HP ZBook 15u G3 Workstation Review

Keyboard

The ZBook 15u G3’s keyboard is, by our judgment, very good overall. It features good feedback and medium length stroke, similar in feel to that of the Dell Precision M5510. The actuation force is on the lighter side, which makes for a comfortable and effortless typing experience, but which does require some adjustment coming from more traditional keyboards (especially standalone models). Keystrokes are fairly quiet and the surface, which feels like it’s made out of carbon fiber, is smooth and durable. We also didn’t encounter many problems with fingerprints. Perhaps the only criticism we have with regard to the design is the layout of the arrow keys; the Up and Down keys are a half size and somewhat more difficult to operate.

The keyboard is backlit and key visibility is good. To the right of the keyboard is a full-sized number pad, which those doing a lot of data entry are sure to appreciate.

Touchpad

The Synaptics touchpad is large and responsive, and pointer accuracy is good. The surface is smooth and finger gliding is effortless, making gestures easy. The two buttons (as well as the two above the pad for use with the TrackPoint) have a loose feel and rattle about when first touched, but they’re still mostly quiet in their operation and they provide a satisfying soft “click” for feedback.

Touchscreen

Our particular review unit configuration included a touchscreen. The smooth, glossy surface likes to collect fingerprints, but the touch interface itself is accurate.

Our measurements confirm our suspicions: while the brightness is sufficient at 283.8 cd/m², and the brightness distribution of 89% results in a good consistency across the breadth of the display, the contrast of just 351:1 (thanks to a predicted high black value of 0.849 cd/m²) results in a rather washed-out appearance. Here, the ZBook 15 G2 even handily wins (slightly better brightness and much better contrast), and the ThinkPad W550s and especially the Dell Precision M5510 put it to shame (360 cd/m² and 391 cd/m² respectively on brightness and 667:1 and 978:1 on contrast). PWM was also conspicuously present at all brightness values below 100% (more details on that below).

Color coverage is—again, as we had presupposed—merely decent. We measured sRGB coverage of 80%, which fall short of the competition by a significant margin. AdobeRGB is, of course, even more deficient, with just 51% of the spectrum addressed. In comparison, the ZBook 15 G2 managed nearly 64%, the W550s 56%, and the Dell Precision M5510 a whopping 96%.

Our measurements for the IPS 1080p panel, meanwhile, reveal a much better color coverage of 98% of sRGB and 64% of AdobeRGB.

Our CalMAN 5 measurements produced a ColorChecker pre-calibration deltaE 2000 average of 8.68 and a Greyscale deltaE of 9.3, both of which are very high for a professional workstation. In comparison, the competition manages values consistently below 5 in both categories, save for the ZBook 15 G2’s outlier of 5.94 in dE Greyscale. The CCT Average of 10585 is also significantly skewed toward the cool side of the spectrum. The Total Gamma of 2.27 is at least good.

Below are measurements from the 1080p Full HD IPS configuration, which are considerably better:

Outdoors, the ZBook 15u G3 touchscreen configuration struggles mightily thanks to the high-gloss panel finish, which some touch-enabled competitors (such as the Lenovo ThinkPads) thankfully lack. The other display options provide anti-glare finishes and should fare much better here. Viewing angles are also a serious disappointment, with off-axis viewing quickly washing out and inverting colors. Again, the other display options, two of which are IPS panels, should completely correct this.

The particular CPU in our ZBook 15u G3 review unit is the Intel Core i7-6600U, which is a dual-core chip based on the Skylake architecture. It’s a ULV CPU carrying a TDP of just 15 W—something which (in addition to its lack of quad-core functionality) traditionally might preclude its inclusion in a mobile workstation. However, we’ll leave the determination of whether this is a concern up to our benchmarks.

The Core i7-6600U has a base clock rate of 2.6 GHz, with Turbo frequencies of up to 3.4 GHz (single-core) and 3.2 GHz (dual-core). We already have a fair number of benchmarks in our database for this processor; it’s certainly powerful enough for everyday activities, but of course, the limitations of a dual-core chip should be considered before deciding on something as critical as a professional workstation.

Compared with other machines powered by the same CPU, the ZBook 15u generally manages to land in the center of the pack, just below the ThinkPad T460s and Surface Book in most cases and just above the ThinkPad T560 and Elitebook 840 G3. The results are not greatly varied, however, only a 4 to 5 percent difference in either direction.

On the other hand, as compared with workstations equipped with quad-core CPUs, the 15u G3 is predictably beaten on a consistent basis. The Dell Precision M5510 leads the pack, absolutely demolishing the ZBook’s score of 3.67 points in Cinebench R11.5 CPU multi and 330 points in Cinebench R15 CPU multi by 116% and 122%, respectively (see our graphs below for the hard numbers). Even the older ZBook 15 G2, with its Haswell chipset, is nearly twice as fast in these benchmarks, winning by margins of 92% and 97% thanks to its quad-core Core i7-4910MQ. Of course, when we turn to single-threaded benchmarks, the advantages collapse—because then we’re no longer weighing the benefits of the two additional physical cores. Here, the ZBook 15u G3 holds its own.

CPU performance is only one aspect of the total performance equation, of course, and insofar as pure system performance is concerned, the ZBook 15u G3 is no less speedy than its peers. Subjectively speaking, we agree: the machine is indeed quite nimble, able to zip through program installations, startup and shutdown procedures, and other everyday application demands without any hint of a flinch.

PCMark 7 and 8 both reveal scores that match the Dell Precision M5510 almost precisely and which top the older ThinkPad W550s. Oddly enough, the HP ZBook 15 G2 comes out on top here, with advantages ranging between 6 and 17 percent faster… but ultimately, at these speeds, we’re splitting hairs.

Even in spite of a low noise profile, the ZBook 15u G3 never gets too terribly hot under load. With room temperatures within a degree of one another in each of the analyzed sets of data, we measured surface temperatures of just 33.9 °C and 37.1 °C on top and bottom respectively under load. This is as compared with 35.8 °C / 37.1 °C for the Dell Precision M5510 and a much hotter 36 °C / 41.2 °C for the older ZBook 15 G2, which looks quite good for the G3. Only Lenovo’s W550s can decisively defeat it with values of 31.1 °C and 33.1 °C respectively. Furthermore, we measured no particular hot spots, though the center of the keyboard reached 44.6 °C and the top-center quadrant of the underside managed 46 °C.

Of particular interest with regard to mobile workstations is how well they can handle a heavy processing load thrown upon either the CPU or GPU (or both). We use Prime95 and FurMark to simulate heavy system load during our stress testing procedures.

During full CPU stress using Prime95, the CPU quickly bottoms out at between 2.8 and 2.9 GHz per core, which is 0.3 GHz below the top-end Turbo frequency. It’s unfortunate that the ZBook cannot maintain max Turbo frequencies for longer given its intended use. The limitations are not thermal (we recorded a max temperature of just 61 °C for the CPU Package), but rather rooted in TDP.

GPU stress produces frequencies bouncing back and forth between 675 MHz and 800 MHz, both of which are once again below the maximum turbo frequencies of the adapter (900 MHz). Once again, with a chip temperature of just 73 °C, the constraints are not thermal in nature.

With combined CPU and GPU stress, not much changes in terms of performance, except the GPU frequency no longer makes its occasional jumps to 800 MHz and instead remains practically locked at 675 MHz. The CPU also remains at 2.8 GHz for the most part. Temperatures climb precipitously up to the 87 °C mark, but they are managed by a combination of throttling and higher fan speeds back down to a cooler 80 °C.