Review Update Lenovo IdeaPad Yoga 11S Convertible

For the original German review, see here.

The IdeaPad Yoga 11S delighted us with its bright display, its stable build quality, and good touchscreen three-quarters of a year ago. The high temperature increase under load, the somewhat cumbersome handling in tablet mode and the keyboard with weak feedback were points of criticism. The complete review is available here. Lenovo updated the model with the new processor generation from Intel with the codename Haswell. We checked whether the strengths remained and flaws were straightened out.

We compared the test model to convertibles for private use like the Dell XPS 11, the Asus Transformer Book Trio and the Gigabyte Padbook S1185. The devices from Dell and Asus are already based on the new Haswell platform, too.

Since case and connectivity remained the same, we will start with the display right away. We accurately re-measured the brightness: The display of the Haswell model is not quite as bright as the IdeaPad Yoga 11S predecessor's. But, they have the same display incorporated: an AUO205C from AU Optronics.

With an average brightness of 315 cd/m², the display is about 20 cd/m² darker than the IdeaPad Yoga 11S's with Ivy Bridge processor. Nevertheless, it is still sufficiently bright and ranked mid-table among the devices in comparison. The black value of 0.41 cd/m² is also good and allows reproducing deep black areas in images.

The Intel Core i5-4210Y features two cores and a clock rate of 1.5 GHz on paper, which equals the Core i5-3339Y Ivy Bridge predecessor's with a higher power consumption. You should be well equipped for office applications and multimedia with it.

CPU performance

However, Cinebench R11.5 reveals significant differences to the predecessor: The Haswell processor in the Lenovo IdeaPad Yoga 11s is even slower than its Ivy Bridge predecessor. The Dell XPS 11, which also features an Intel Core i5-4210Y, performs significantly better, too. So, it seems likely that the Turbo of the Haswell model's CPU was slightly slowed down in favor of lower emissions.

Intel specifies a Scenario Design Power (SDP) of 6 Watt, which is significantly lower than a TDP of 11.5 Watt. SDP allows the SoC to work at a lower power level than SoCs with only a specified TDP (all non-Y CPUs). If the cooling system is sufficient, the CPU can work at a higher power level (up to the TDP). However, this does not appear to be possible here. See the stress test below. Lenovo has set the temperature limits very conservatively.

The Lenovo IdeaPad Yoga 11S with current processor is also outperformed by the model with Ivy Bridge CPU and the Dell XPS 11 in PCMark 7. It scored about 250 points or about 7% lower than the Lenovo IdeaPad Yoga 11S with Ivy Bridge CPU. The performance could be either limited due to the SSD or CPU throttling under full load. We will explore these two aspects a little later in this review.

The SSD with 128 GB in our test model performs slightly worse than the SSD with 256 GB in the IdeaPad Yoga 11S with Ivy Bridge processor in CrystalDiskMark 3.0. While both hard drive models stem from Samsung and deliver transfer rates and access times more than suitable for everyday tasks, the model with 256 GB is slightly faster. In particular, the read rates are mostly significantly higher.

The Intel HD Graphics 4200 is a significant advancement compared to the HD Graphics 4000 of the Ivy Bridge generation. However, the clock rate was again significantly reduced. So, the performance should be about the same level. Nevertheless, our test model performed significantly better than the IdeaPad Yoga 11S with Ivy Bridge Core i5 in 3DMark 11. The Dell XPS 11 cannot keep up with our test model either. Gamers are limited to simple or older games and usually these cannot be played with maximum screen resolution.

3D games of the last year like Tomb Raider can only be played reasonably smoothly with significantly reduced resolution and heavily reduced details. If you prefer casual games or browser games anyway, you do not need to worry: processor and graphics card are sufficient for these.

It is interesting that the system noise of the IdeaPad Yoga 11S with Haswell processor is also slightly lower than the Ivy Bridge model's. This might be due to the lower power consumption and the lower waste heat of the processor.

Since the fan is on the rear side, the noise level is low anyway. While idle you need to be very close to the fan to hear it at all. However, the fan runs continuously. Under full load the cooling system becomes audible, but the noise level remains comfortable with a maximum of 36.1 dB(A) and is still just under 2 dB quieter than the Lenovo IdeaPad Yoga 11S's with Ivy Bridge processor.

The temperature increase under full load was a disadvantage of the Lenovo IdeaPad Yoga 11S with Ivy Bridge CPU: The underside reached up to 52.8 °C. Unfortunately the upgrade to the new processor generation did not improve this: our infrared thermometer still displays 52.5 °C. But, the situation improved on the upper side with a maximum of 39.6 °C. The temperatures are also lower while idle: maximum of 31.1 °C on the underside versus 34.4 °C of the Ivy Bridge model.

During everyday tasks you can also use the device on the lap. However, during more demanding applications you should use the Lenovo IdeaPad Yoga 11S with Haswell CPU on a pad or directly on a desk.

Power Consumption

Unfortunately, we do not have detailed data of the power consumption of the IdeaPad Yoga 11S with Ivy Bridge processor. Battery life (see below) and batteries with the same capacity imply that the Core i5-4210Y's power consumption is significantly lower than the Core i5-3339Y's of the Ivy Bridge generation and that this also has a significant impact on the energy demand of the whole system. Since the Haswell generation Intel also specifies the Scenario Design Power, i.e. the power consumption measured during various benchmarks, which should conform to the typical power consumption during everyday use: While the Thermal Design Power, i.e. the power required to sufficiently cool the processor, is 11.6 Watt, Intel specifies an SDP of 6 Watt.

So, the IdeaPad Yoga 11S is about on par with the Haswell competitors Dell XPS 11 and Asus Transformer Book Trio here. Dell's XPS 11 has slightly lower maximum power consumption, but our test model has the lowest average power consumption while idle with 7 Watt.

While we only had the first test results of Haswell CPUs when we reviewed the IdeaPad Yoga 11S with Ivy Bridge processor, they showed that Haswell could significantly improve battery life. So, our expectations in the test model were high since its Intel Core i5-4210Y processor's thermal design power (TDP) is 1.5 Watt or 11.5% lower than the Core i5-3339Y's of the Ivy Bridge generation. In addition, the graphics card is now integrated into the chip and does not require extra energy. The capacity of the lithium-polymer battery of 42 Watt hours remained the same. This allows a direct comparison of battery life.

The test model indeed runs above one hour longer than the IdeaPad Yoga 11S with Ivy Bridge processor in our realistic WLAN test: 6:27 hours. The battery life does not change greatly under full load, but the new processor generation allows using the laptop about 1:40 hours longer while idle. In addition, our test model is roughly on par with current Haswell competitors like the Dell XPS 11 with about the same battery capacity.