联想ThinkPad螺旋3G换股测评

As revolutionary as this construction may seem - many of the traditional ThinkPad design virtues have carried over to Lenovo's most recent convertible. Sure, rounded corners and a slim chassis may render the Helix unfamiliarly thin, but the well-known subtle, if somewhat outmoded visual design language and its grayish-blackish color scheme remain unmistakable.

All of this should not be able to conceal that this is actually a high-end device. Thanks to a modern magnesium-PC/ABS composite, the tablet only weighs 835 grams (exactly the same applies to the keyboard dock as well, bringing the total weight to 1.67 kilograms). For reference: The much slower HP Envy X2 weighs more than 700 grams, the smaller (10.6-inches instead of 11.6-inches) Microsoft Surface Pro even more than 900 grams (both measured without their respective "docking stations"). The Helix is even lighter than Lenovo's own X230T which measures 1.8 kilograms, aiming at a rather similar segment of the market. Even for prolonged periods of time, Lenovo's tablet can be held with just one hand.

The connection between the display and the dock has been the subject to much fine-tuning, as the quality-spoilt business customers of the ThinkPad series would expect, trying to find the sweet spot between maximum flexibility, great ergonomics and stability, a ThinkPad strength. Luckily, the manufacturer has managed to solve this problem rather well: The tablet can easily be removed with a simple push on a lever and be re-attached without hassle as well - even reversed by 180 degrees, if this is required. Unfortunately, the display wobbles slightly in its holder, but not enough to become noticeable during actual usage. Apart from this one minor quirk, everything about the construction seems well-designed and extremely sturdy.

The same quality standards do not seem to apply to the keyboard dock. While generally well-built, it could be more torsion-resistant. Applying pressure to the case leads to visible deformations at certain locations. Obviously, Lenovo has tried to find some kind of compromise between stability and weight. Still, the ThinkPad Helix is more than decent in terms of its overall build quality.

Thanks to its high brightness (which is only available in battery mode when the energy saving mode of the Intel graphics card is deactivated), the Helix is well-suited for outdoor usage, as long as it is not exposed to direct sunlight. Due to its non-matte surface, a workspace in the shade is required to be able to work well with the device, as its scratch-proof, easily cleanable Corning Gorilla Glass display is extremely glossy.

Another advantage of high-quality IPS panels next to great image quality: Viewing angles are superb. Even when viewed from very narrow angles, the screen contents remain discernible, showing no signs of color deviations or overly strongly decreasing contrast ratios. This is especially important while using the Helix as a tablet where the user is able to operate the device in every orientation. Even the best TN panels fare far worse in this regard.

Since Lenovo already revealed the ThinkPad Helix at the CES in Las Vegas at the beginning of the year, it is still based on Intel's Ivy Bridge chip generation instead of Haswell, being equipped with ULV processors ranging from the Core i5-3317U to the high-end Core i7-3667U.

The Core i5-3317U used in our test device sports two CPU cores with a base clock speed of 1.7 GHz which can increase to up to 2.4 GHz (two cores) or 2.6 GHz (one core). In addition, Hyperthreading technology boosts performance in well-parallelized applications, allowing each core to work on up to two threads simultaneously. Despite of its more than decent performance, the 22 nm Core i5 chip sports a TDP (thermal design power) of just 17 watts. However, the more recent Haswell variants are even less power-hungry, requiring only 15 watts for the entire chipset.

Since the Helix is intended as a business device, graphics performance is secondary. The integrated HD Graphics 4000 clocked at 350 to 1050 MHz in our case is more than sufficient for multimedia purposes as well as simple 3D applications.

More of an issue (and not really understandable, given the price point of the device) is the low amount of RAM: 4 GB, working at a reduced clock speed of 666 MHz (DDR3L-1333, dual-channel). This reduces performance levels especially in graphics-intense usage scenarios, as will be seen in some benchmarks below. The ThinkPad Helix offers 180 GB of SSD storage for applications and user data.

Due to the Helix's slim profile, the only SSDs used in Lenovo's newest ThinkPad are those of the mSATA variety, offering capacities ranging from 128 GB to 256 GB.

Our test device comes equipped with a 180 GB Intel SSD 525 (code name Lincoln Crest, SSDMCEAC180A3L), which was revealed a few months ago. The SSD-525 series is closely related to the older SSD 520 2.5-inch variant. Both use the Sandforce Controller SF-2281 with Intel's own firmware which is combined with 25 nm flash memory modules in an MLC architecture.

The SSD 525 is almost as fast as its non-mSATA sibling, yielding some of the best results of all SSDs. Sequential data transfer rates of up to 466 MB/s (reading) are superb, as is its speed when working with smaller files. On top of that, Intel's SSDs have a reputation of being very reliable, which fits the professional focus of the ThinkPad Helix.

Those who still want to use the Helix as a gaming device will often have to adjust graphics quality to the lowest possible setting, and, at least in newer games, reduce the display resolution down to 1024x768 pixels, if at least some degree of smoothness is desired. This shouldn't be an issue for Lenovo's target audience though, as gamers will probably choose a larger laptop or ultrabook with a dedicated graphics card.

Unfortunately, the low noise emissions correlate with rather high chassis temperatures. Even while the tablet is idle, we measure temperatures of much more than 30 °C, especially on the right hand side. It gets far worse, though: Under full load, more than 65 °C is reached - such a high temperature has rarely been recorded in one of our reviews, even with power-hungry high-end devices. Even when the most notorious hot spots are excluded, the back of the device gets 50 °C warm - on average. Those who don't want to risk getting burned will probably prefer to lie the tablet down at this point.

Our results will have to be put into perspective though. In most usage scenarios which lead to these temperatures, the tablet will probably be used with its keyboard dock, thus sparing the user from coming into contact with the (rear of the) device. The keyboard dock itself remains absolutely cool at all times. Typical tablet usage (browsing, HD videos, etc...) is far less taxing, resulting in a tolerably warm device. Surprisingly, the innards never get critically hot. E.g. the Core i5-3317U plateaus at around 90 °C after one hour of our combined Prime95 and FurMark stress test, remaining at 2.1 to 2.2 GHz. The GPU can use its Turbo as well, reaching almost 1000 MHz. Thus, even during the summer, no throttling is likely to occur.

The ThinkPad Helix fits very well into Lenovo's existing product portfolio. However, it also raises the question "why so late"? The basic idea of a full-fledged x86 tablet (even when used without the keyboard dock) offers an invaluable advantage in terms of mobility: No conventional convertible can ever get so light and compact when necessary.

Its technical components are almost exclusively well-chosen too. Traditional ThinkPad strengths such as excellent build quality, great input devices and low noise emissions are still present. We were quite impressed by the high-contrast, high-brightness Full HD multitouch display with great viewing angles which can be controlled with a digitizer pen as well.

Unfortunately, there are also some details which might require some revision. Just 4 GB of RAM may not be enough for more demanding programs - and it cannot even be expanded. This complaint holds true for the entire device: When compared to other ThinkPads, there are very few options in terms of expandability, maintenance and connectivity - one of our main points of criticism next to the uncomfortably high chassis temperatures under full load.

Overall though, the Lenovo ThinkPad Helix is not only an innovative product, but also a convincing one. At a price: Even our entry-level variant costs a steep 1700 Euros (~$2218), while Lenovo charges almost 2000 Euros (~$2609) for the high-end variant with a Core i7 CPU, 8 GB of RAM and a 256 GB SSD. This is definitely no steal, but still a fair price when considering everything the Helix has to offer.