Review Lenovo ThinkPad T431s Ultrabook

The ThinkPad T431s is Lenovo’s first model to incorporate the manufacturer’s new design philosophy and is expected to be a blueprint for future models in the T Series. Users who have worked with the X1 Carbon first-hand will already be familiar with some of these changes; If the X1 Carbon and T430s had a child, this new model would be it.

The locking clamshell latches are now gone, the surfaces are flatter with smaller feet and the system does indeed give a much cleaner and more simplistic impression. The outer lid is now made of smooth carbon fiber combined with a magnesium body and integrated roll cage to preserve as much of that exceptional build quality that has made previous ThinkPads a household name. The dual hinges are also smaller in size compared to the previous T430s, but are able to anchor the lightweight display with no residual vibrations while typing. Both side-to-side twisting of the base and depressions on the palm rests, keyboard and outer lid are thus very minimal, though still a tad visible. We’ll admit that a handful of older ThinkPad models do feel stiffer and thicker, such as the T530, at the obvious cost of weight and portability.

Speaking of weight, the T431s is the thinnest and lightest T Series model to date. At 1.56 kg and 20.6 mm thick, the unit compares very favorably against the T430 (2.33 kg, 29.9 mm), the T430s (1.79 kg, 26 mm), the T430u (1.9 kg, 21 mm), and even the brand new Dell Latitude 6430u (1.8 kg, 20.9 mm). The competing HP EliteBook Folio 9470m does come in thinner, but its lower resolution display may turn off users.

A new change that has brought about mixed feelings is the narrower display bezel width. The thin, plastic-like bezel has always been a weak area of ThinkPads and thinning it without increasing rigidity may not be the best way to go. Twisting of the lid, for example, is now slightly easier than on previous models. It’s true that a thinner bezel will make for a more attractive display, but we find longevity to be more important than looks for a notebook series made for business users in mind. Even so, this is only a minor complaint as the T431s still upholds MilSpec standards and is leagues beyond what most other consumer Ultrabooks can offer in terms of construction and end-user upgradeability.

Keyboard

The spill-resistant AccuType Precision Chiclet keyboard (28.5 x 11 cm) appears here as it does on the T430s, but with two notable differences. For one, the keys on the T431s now provide much deeper travel – more so than other similarly-sized notebooks – for a much more satisfying typing experience. Feedback is firm without any of the sponginess that other Ultrabooks with Chiclet keyboards tend to offer and it was very easy to begin typing on the T431s without the need to first become accustomed to the feel or layout. The arrow keys are unfortunately still reduced in size and may be more difficult to use for those with larger fingers. Two levels of keyboard backlight are also available and they make up for the absence of the ThinkLight. Oddly enough, the opposite is true for the T430u.

The second major change is its overhauled top row of keys. Gone are the dedicated volume, microphone, and even the ThinkVantage keys in favor of more multi-function F keys that are commonly found in consumer Ultrabooks. This simplifies the keyboard for a cleaner look and impression. Thankfully, users can toggle Fn lock to easily switch between the traditional function keys and their auxiliary commands.

Touchpad

The old textured trackpads of previous T Series models are sometimes criticized for their small sizes and redundant click pads, but Lenovo looks to finally change things up starting with the T431s. Replacing the 7.5 x 4.5 cm touchpad of the T430s is a new and admittedly large 10 x 7.5 cm glass touchpad with integrated click keys. The removal of the dedicated click keys has allowed for the massive increase in surface area. The matte surface is leveled with the palm rests and feels completely smooth as opposed to the textured bumps on previous models. This same design is expected to make its way onto the upcoming ThinkPad Helix.

The redesign certainly looks fantastic, but how does it perform? Fortunately, as good as it looks. The larger surface area provides the obvious benefit of both easier navigation and multi-touch gestures, the latter of which now supports up to 4-finger commands. The entire area can be clicked, and clicking anywhere produces an equal amount of travel and feedback, both of which feel deeper and more responsive than most other Ultrabooks.

All five mouse buttons of previous ThinkPads return here as integrated keys on their respective locations. For example, clicking the upper center of the touchpad will imitate the old middle scroll input. For word processing and general use, we found the notebook to be easier to jump into should an external mouse be unavailable. Of course, the traditional Track Point returns intact for those who prefer it over the touchpad.

Color reproduction is very similar to that of the T430s and Dell Latitude XT3 despite the latter having an even brighter screen and more impressive contrast than all the ThinkPad T Series models mentioned in this review. Coverage of the sRGB spectrum is about 58 percent, too low for professional digital graphics work but sufficient for everyday word processing and browsing. More expensive workstations, such as the Lenovo ThinkPad W Series, are equipped with the necessary panels and WCG backlighting to produce a wider range of colors.

Color accuracy was further analyzed with an X-Rite spectral profiler. Out-of-the-box, the T431s produced very inaccurate colors in all saturation levels and a very blue grayscale due to the high color temperature. Post calibration results fared much better with most colors falling at or below the 5 DeltaE 2000 mark and a more tamed grayscale. Color temperature does remain slightly blue, and this is reflected upon the increasingly inaccurate representation of the color at higher saturation levels.

We subject the T431s to synthetic stress with monitoring tools CPU-Z, GPU-Z and HWiNFO in order to identify potential throttling issues. With Prime95 active, both CPU cores were observed to be operating at their maximum 2.7 GHz Turbo Boost without any hitches. Similarly, FurMark was able to bump the GPU from its base 350 MHz clock to 1200 MHz, but quickly dropped to a stable 1050 MHz. The CPU core peaked close to 70 degrees C in both cases.

With both Prime95 and FurMark active simultaneously, the CPU was unable to sustain any of its Turbo Boost benefits and quickly dropped to maintain its base 1.9 GHz clock rate. The GPU experienced a drop as well, albeit almost insignificantly from 1050 MHz to a more stable 950 to 1000 MHz. During the hour long stress, we experienced no glitches or instabilities with the hardware and a 3DMark 06 test immediately following the test resulted in essentially the same scores. Since the CPU never dropped below its base clock rate during the test, we observed no throttling issues with the T431s.

Running on batteries will result in stinted GPU performance, even in High Performance. A 3DMark 11 run returned unaffected Physics (CPU) scores, but GPU scores were cut by more than half (528 points on AC power vs. 214 points on batteries). According to GPU-Z, the HD 4000 will remain at its base 350 MHz clock if not on AC power.

All T431s models include an integrated Li-ion 3-cell 47 Whr battery, similar to the module as found on the T430u with no other capacities available. This is opposed to the heavier 6-cell 44 Whr module on the T430s, though the latter is user-removable and can easily be swapped without needing to remove the bottom panel. Instead, secondary Ultrabay batteries can be connected to the T431s for extending battery life if needed.

The integrated battery should provide up to 9 hours according to Lenovo. According to our own test with the Battery Eater Reader’s Test, we were able to reach 8 hours and 36 minutes by allowing the notebook to sit idle with wireless disabled and on the lowest brightness setting – hardly an ideal situation. To record our minimum runtime of about 1.5 hours, the Battery Eater Classic Test was used on maximum screen brightness with active wireless.

The more realistic middle-ground WLAN test puts the notebook on 150 cd/m2 brightness (setting 7/10) while looping our standard script to simulate typical browsing conditions. Under these conditions, the T431s was able to last for about 4 hours and 45 minutes before automatic shutdown.

Based on our results, users can expect 5 to 6 hours of constant use depending on the workload and brightness setting. The high idling runtime means users can squeeze out a bit more from the T431s by fine-tuning system settings and other power-sipping features. This compares favorably to the T430u and Latitude 6430u, both of which clocked in somewhere between 3 and 4.5 hours in the same WLAN test. The X1 Carbon can last notably longer despite having a slightly smaller battery capacity, but the HP EliteBook 9470m outlasts them all by a wide margin at an impressive 7.5 hours in WLAN mode.