Not changing a winning formula is an adage that Lenovo seems to be sticking to for its premium ThinkPad X1 Carbon series.

Now into its sixth iteration, this year's X1 Carbon has a near-identical design as its predecessor.

The ports have been reworked slightly and the processor has been updated to the latest Intel Core chip. There is also an option for a cover (dubbed ThinkShutter) for the front camera, which is not found on my review set.

But it is still as sleek and handy as last year's version. It weighs about the same (1.13kg), which is impressive for a laptop with a 14-inch display. It is not quite as portable as the LG gram series, which weighs less than a kilogram, but the Carbon feels more sturdy and rigid.

No doubt Lenovo has learnt its lesson from 2014, when it replaced the Function key row on the Carbon's keyboard with a touch-sensitive version that changes options depending on the context - sort of like the touch bar on the current Apple MacBook Pro. This move was not welcomed by ThinkPad users and the physical buttons were back the following year.

I am glad to report that Lenovo has kept the same excellent keyboard with just the right amount of depth and tactile response. The iconic ThinkPad TrackPoint pointing stick, the red nub in the middle of the keyboard, is present, too.

But I wished Lenovo would change the placement of the Function and Ctrl keys at the lower left corner.

On ThinkPads, the Function key is at the most extreme corner instead of the Ctrl key, unlike other laptops. Although the key assignments of the two can be swopped via the Bios setting, it would be so much more convenient if I did not have to do this anymore for ThinkPad laptops.

My review set comes with two different biometric authentication features: an infrared (IR) front camera for facial recognition and a square-shaped fingerprint scanner beside the touchpad.

You probably need to pick just one, as both unlock the laptop promptly. However, the IR front camera does not come with the front camera cover option. So if you need the cover's added privacy, your only choice is the standard 720p front camera that lacks facial recognition.

New to this model is the option for a Dolby Vision-compatible HDR display that produces up to 500 nits of brightness compared with 300 nits for the standard screen.

While I would have liked to try it out with Netflix's HDR titles, this feature will be available only in August.

In any case, the standard 1,920 x 1,080-pixel screen on my unit is still a very good display with lively colours and slim bezels. With some laptops, like the ones from Microsoft, sporting a 3:2 aspect ratio that is optimised for productivity, perhaps Lenovo could consider tweaking its screen to this ratio for the next iteration.

The X1 Carbon stayed cool and quiet throughout my benchmark testing. It scored 3,970 points in the PCMark 10 benchmark, which is slightly higher than the similarly equipped HP EliteBook 830 G5.

Battery life is excellent, with the laptop clocking more than nine hours in the video-loop battery test at maximum brightness and volume. This is about 1.5 hours longer than another business laptop, the HP EliteBook 830 G5, that I had tested recently.

Lenovo's online store lets buyers customise the X1 Carbon to a relatively large extent compared with other PC brands. My review set works out to about $3,893, which is pricey, even for its high-end specs.

• Verdict: Sleek and attractive in black, Lenovo's premium X1 Carbon is still one of the best laptops in the market.