Lenovo IdeaPad S540-15IML laptop review: Terrific battery life

The S540-15IML's competitors include other MX250-based 15-inch laptops such as the Acer Aspire 5 A515-52G-723L, the HP Pavilion 15-cs2019ng or the Asus VivoBook S15 S532F. The latter laptops appear in the tables as comparison devices.

Since Lenovo hasn't made any changes to the chassis except for the display frame (it's glossy with the glossy version instead of matte), we won't revisit the case, connectivity and input devices. You can find the relevant information in the predecessor's review.

We don't think it's a good idea for a manufacturer to opt for a reflective display. In the past, glossy displays were mainly used to disguise the poor image quality of inferior TN panels. In times of IPS panels, however, there's hardly any reason for glossy monitors, unless you want to strain the eyes unnecessarily. Even under low sun or light exposure, the IdeaPad S540 is prone to strong reflections that make working pleasantly almost impossible. The only time the display isn't disturbing is when it's in completely darkened rooms.

The color space is also satisfactory at 86% sRGB. For comparison: The Acer Aspire 5 and the Asus VivoBook S15 can't even reach 60% sRGB coverage. Attention: The display flickers under a brightness of 100%. A frequency of 200 Hz can cause problems in sensitive users.

With the help of the preinstalled Lenovo Vantage software, various settings can be carried out on the system. Our tests were performed with the standard settings, which are active out of the box.

As mentioned at the beginning, the base clock speed is 1.6 GHz. With Intel's Turbo Boost technology, a maximum of 4.2 GHz can be squeezed out from the CPU. However, the latter is only achieved in single-core scenarios. In multi-core scenarios, the S540 doesn't fully exploit its Turbo. In this way, the clock speed dropped from 3.5 to 3.7 GHz to a mediocre 2.8 to 2.9 GHz after a short period of time in our Cinebench loop.

Despite the limited Turbo, the Core i5-10210U easily moves past the older Core i7-8565U and Core i5-8265U Whiskey Lake models. As you can see from the table below, the performance increase amounts to just under 40% in the best-case scenario.

Although the results of the PCMark 10 benchmark hardly differ, the IdeaPad S540 is also at the top of the comparison field in terms of system performance. Thanks to the solid state drive, using the operating system (Windows 10 Home 64-bit) feels very fluid.

Similar to its competitors, Lenovo relies on an M.2 SSD with PCIe/NVMe technology. The 512 GB Samsung PM981a is one of the fastest representatives of its kind when it comes to both writing and reading operations. Next to the WDC PC SN520 (Acer Aspire 5, Asus VivoBook S15), the Toshiba SSD of the HP Pavilion 15 is also noticeably slower to some extent.

The performance of the graphics card turned out to be less spectacular. For example, while the GeForce GTX 1650 mid-range GPU represents a worthwhile upgrade to the GTX 1050, Nvidia is getting nowhere with the MX250 entry-level model. The 14 nm chip from the Pascal generation is only intended for undemanding and/or older 3D applications due to its poor features (384 shaders, 2 GB VRAM, 64-bit memory interface). The GTX 1650 mentioned above is the minimum for gamers to be happy. The MX250 should primarily be seen as an all-round GPU for a small budget.

We checked the clock speed behavior of the DirectX 12 graphics card with the role-playing game The Witcher 3. After 60 minutes of running the test, the clock speed settled at about 1,500 MHz, with values fluctuating between 1,400 and 1,600 MHz. Given the 1,519 MHz base clock speed, this result is somewhat disillusioning (Turbo is hardly used).

Surprisingly, the IdeaPad S540 performs quite boldly in our benchmarks and ranks slightly ahead of the competition in the 3DMark tests. Via Optimus, the 15-inch device can dynamically switch between the processor's graphics chip (UHD Graphics 620) and the dedicated Nvidia GPU.

At its native Full HD resolution of 1920x1080, the GeForce MX250 reaches its limits very quickly. High to maximum details are usually not possible in modern games. Even medium details often result in stuttering, which is why you should limit yourself to 1366x768 or 1280x720 pixels if necessary.

Less processor-intensive titles such as FIFA 20 and Farming Simulator 19, on the other hand, run smoothly even at higher quality levels.

One of the greatest strengths of the IdeaPad S540 is its moderate noise and heat development. Although the cooling system sometimes turns up a little in idle mode and in simple activities related to office work, video playback and web surfing, the device is very quiet (32 dB) or completely silent most of the time. 

In 3D mode, the 15-incher doesn't mutate into a squaller either at 39 to 42 dB, whereby the fan noise is subjectively louder than on paper due to the relatively high frequency.

The case surfaces are also anything but hot-headed. A maximum of 42 °C (~107.6 °F) at the top and 45 °C (~113 °F) at the bottom after 60 minutes of running Furmark + Prime95 is completely in order. Longer work sessions are no problem either given the idle temperature of approximately 25 °C (~77 °F).

As long as the GeForce GPU is inactive, the 15-inch is very economical. 5 to 10 watts of idle consumption is reminiscent of the competition's values. Under load, our measuring device showed between 44 and 67 watts – also typical of an all-round laptop with a ULV CPU and low-end GPU.

The absolute highlight of the IdeaPad S540 is its excellent battery life. It reached up to 30 hours in the Reader's Test of the Battery Eater tool (minimum display brightness), a value that almost no other laptop achieves. With this result, the Lenovo computer trumps the competition by two to four times!

Almost 12 hours of runtime when surfing the Internet via Wi-Fi (medium brightness) is also remarkable and deserves the greatest respect. There's also praise for the fact that 3D performance remains constant on battery power (tested with The Witcher 3 in FHD/Ultra).