Schenker XMG U506 (Clevo P751DM) Notebook Review

The 15-inch notebook's case, P751DM, is a product of the Taiwanese expert gaming company Clevo. Since it is very similar to its predecessor, the P751ZM, we saw no need to write a new version of our "Case", "Connectivity" and "Input Devices" sections. More information on these is available in our review of the XMG U505. Except for a few minor details, the new barebone is more or less a clone of its predecessor.

We are somewhat surprised that the manufacturer has chosen another Full HD panel for this device. This could be related to the G-Sync support, and/or the notebook's pre-production status. As well as the display, the BIOS, the pre-installed software and the fan control system may change by the time Schenker releases the final product.

Back to the display: Unfortunately, apart from the brightness, the LP156WF6 panel from LG Philips cannot keep up with the old AU Optronics B156HAN01.2. Since the XMG U506's black value is nearly twice as high (0.42 vs. 0.23 cd/m²), the panel manages a contrast of only 710:1 rather than 1087:1. The CalMAN software, which performs professional display evaluations, also revealed lower test scores for our current test device  in almost every discipline. The new panel falls short of its predecessor in terms of grayscale, gamma value, color accuracy and color saturation.

A quad-core CPU, a luxury GPU, 16 GB or DDR4 of RAM and a solid-state drive: With its array of premium components, the XMG U506 is aiming to ascend the performance podium. Not to spoil the surprise: The project was a success. However, whether the product is worth more than 2000 Euros (~$2250), is a question that each gamer will have to answer individually. The laptop's price-performance ratio falls far short of that of desktop PCs. It may be important to note that the high costs are also driven by the slumping value of the Euro, as well as Nvidia and Intel's dominance of the market. AMD often lacks equivalent alternatives, leaving the competition with an advantage that they exploit mercilessly.

Compared to a quad-core mobile processor with Hyperthreading technology, the Core i5-6600K does not have it easy. Because the desktop CPU can only process four threads in parallel (rather than eight), other gaming laptops sprint past the XMG U506 in the configuration that we tested. Need an example? Even with its lower clock frequency (2.5 to 3.5 GHz), the Schenker XMG P505's Core i7-4710HQ runs about 10% faster in Cinebench R15's CPU Multi test. In the single CPU test, on the other hand, the Core i5-6600K wins by a margin of over 20%.

However, good single-core performance or not: If you want a processor that will withstand the test of time, we recommend one that is capable of using Hyperthreading technology. In the XMG U506's case, the i7-6700 and the i7-6700K are available options.

Whether the P751DM Barebone can handle these stronger processor models is a different question. Under full load, even the Core i5-6600K reaches 100°C (212°F). Fortunately, in our normal set of benchmark tests, we did not observe any processor throttling. Depending on the core demands, the processor ran at 3.6 to 3.9 GHz. These are precisely the maximum clock rates listed by Intel.

The XMG U506 deserves some criticism for its 3D mode. As soon as we opened a graphics benchmark or a game, the CPU turbo deactivated itself entirely and did not reactivate until the next boot process. We assume this is a bug. Happily, the problem does not have much of an effect on the performance (the base clock rate is only 400 MHz below the maximum). More information on Intel's Skylake architecture is available in our in-depth article.

The PCIe SSD definitely plays a part in the notebook's phenomenal system performance. 7064 points in PCMark 7 is the highest overall score that we have seen. As the table below shows, neither the XMG P505 nor the XMG U505 had a chance against our test device.

The device came with the 64-bit edition of Windows 10 Pro pre-installed on a 500 GB solid-state drive. Samsung's PCIe x4 model, SM951, takes the proverbial cake. While SATA III SSDs manage 500 to 550 MB/s at most in sequential tests, the Samsung SM951 flaunts its superiority with speeds of up to 1917 MB/s (read) and 1508 MB/s (write) in the AS SSD benchmark. Although the system's performance reading and writing small files hardly profits from the PCIe, our test device achieves an overall score of 2789 points - a new record.

Anything the user prefers not to store on the solid-state drive can be relocated to the secondary storage medium. Even though the 1 TB version of the Western Digital Blue only runs at 5400 RPM (rather than 7200), the drive climbs to over 110 MB/s - an admirable speed for an HDD.

Another advantage: The three digital display outputs (2x DisplayPort 1.2 & 1x HDMI 2.0) allow the user to connect three external displays. Depending on the resolution and the monitor, 60 or 120 Hz can fuel the displays. As long as the graphics card plays along, even at 3840x2160 pixels, display content runs as smooth as silk.

Speaking of power: With a GPU score of 9970 points in 3DMark's Fire Strike test, the XMG U506 behaves similarly to other GTX 980M notebooks, like the Schenker XMG P505. A GTX 970M equates to about 24% slower (7536 points in the XMG U505), and a GTX 960M falls behind by 56% (4418 points in the XMG A505). Clevo does not make any compromises when it comes to the GDDR5 video memory either. Eight GB for the GTX 980M and six GB for the GTX 970M: This deserves respect.

The GeForce GTX 980M is more or less the only notebook model that can render 3840x2160 pixels smoothly at good quality settings. The resource-gobbling “Batman: Arkham Knight” aside, the XMG U506 always managed over 30 fps in the 4K setting - though “Metal Gear Solid V” and “Mad Max” sometimes failed to run fluidly.

Things look much better in Full HD (1920x1080 pixels). Here the GTX 980M easily masters even maximum detail settings and multiple anti-aliasing - a feat that cannot be expected of any other card apart from the GTX 970M (with certain limitations). If the game does stutter slightly, the fault lies with the developer and their sloppy code optimization (did someone say “Assassin's Creed Unity”?).

Note: All benchmarks and emissions tests were performed with the G-Sync deactivated.

System Noise

While most gaming notebooks definitely make themselves heard in 3D mode, the XMG U506 is not too loud, even under full load. A maximum of 45 dB(A) is still in the acceptable range, particularly as the notebook only emitted 33 to 43 dB(A) in the 3DMark 06 test (average: 38 dB(A)). Even though, one of the fans did tend to pulsate, the XMG U506 puts up a good show compared to the competition. Many notebooks reach over 40 dB(A) under medium load.

In idle mode, too, our test device's noise level is comfortably low. 31 to 32 dB(A) is hardly noticeable. Many devices have fans that turn on and off often enough to become irritating, but we did not observe that kind of behavior here. While executing simple tasks, the XMG U506 emits only 34 dB(A).

For more information on the notebook's sound quality, we would like to refer you to our review of the XMG U505. Once again, Clevo has equipped the desktop replacement with a 2.0 system from Onkyo, which performed surprisingly well. The most important feature is probably the Sound Blaster X-Fi MB5 sound enhancement solution. Unfortunately, we were unable to test this software ("No supported audio devices are available").

Power Consumption

The missing graphics switching is particularly noticeable in the areas of battery life and energy consumption. An energy usage rate of 23.1 to 35.0 watts in idle mode is much higher than the 12.0 to 22.2 watts consumed by our test device's 15-inch sibling, the XMG P505.

Compared to the XMG U505, however, Schenker has made progress. A result of 32.8 to 48.3 watts reveals that the Haswell architecture needed far more energy than the new Skylake version - and that despite the fact that the Core i7-4790S has a lower TDP (65 vs. 91 watts). Our test configuration of the XMG U506 was more energy-efficient in 3DMark 06 as well - though just a tad, as the stronger graphics card exerts some influence here. Only in the stress test did the XMG U506's energy usage exceed that of the XMG U505.

As previously mentioned, the XMG U506's battery life will not blow anyone away. Even when the computer has nothing to do and is set to minimum brightness, the 8-cell battery (82 Wh) only lasts for a maximum of 3.5 hours. The XMG P505 held out for five hours in the Battery Eater Reader's Test (the XMG U506 only managed 2.5 hours). For 3D applications, our test device lasts for only 1 to 2 hours.