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Dell XPS 12 (2015) Review - Performance, Battery life and Verdict Review


Dell XPS 12 (2015) – Performance

One of the biggest potential compromises of this machine over a conventional slim and light laptop, or indeed a device such as the Microsoft Surface Book, is that it uses only an Intel Core M processor. Whether you’re talking about the top-end Core M7-6Y75 in this machine or the Core M3-6Y30 in the entry-level version, they’re inherently far slower than Core “i” processors.

Related: Everything you need to know about Core M processors

This is immediately evident in the Cinebench R15 CPU benchmark, which tests raw multi-core CPU power. Here the XPS 12 scored just 172 points, which compares to 309 points for the Core i-equipped Dell XPS 13.

This was felt again in Geekbench 3, where this machine scored 4,267 as opposed to the Dell XPS 13’s 6,242. The gap here being slightly reduced as the rest of this machine’s hardware (fast SSD, fast GPU) evens things out.

Dell XPS 12 (2015)

The real-world implications are that in light use this machine will be perfectly capable and nippy, but as you crank up the workload it will start holding you back sooner than a more powerful machine. In practice I’ve found that having even half-a-dozen tabs open in a web browser proves enough to cause a slowdown in the XPS 12.

Technically, the fairly capable graphics chip on this machine means it can play some games – I recorded a frame rate of 12fps in Unigine Heaven at a resolution of 1,366 x 768 – but you’ll be limited by that CPU speed, so the Dell XPS 12 won’t cope with many 3D titles.

Dell XPS 12 (2015) – Battery Life

If there’s one thing a tablet or thin-and-light laptop has to get right it’s having decent longevity away from a plug socket, and here the Dell XPS 12 fails. Badly.

Using the Powermark battery benchmark, with the screen set to 40% brightness (181 nits) and using a 10 min web browsing/5 min video playback duty cycle, this device lasted less than three hours. By reducing the brightness further and removing the keyboard dock – although attached in our test, the backlight goes off after 30 seconds or so – this could possibly be extended to around three and a half hours, but this remains an atrocious result.

Dell XPS 12 (2015)

I’d expect an absolute minimum of around six hours from a device of this type; ideally I’d want to see eight hours or more. I even re-ran my tests, such was the disbelief at this performance, and the numbers stayed the same. I also tried watching Netflix on the device, and each hour it consumed around a third of its capacity.

What’s more, while the charger is compact in size, it isn’t particularly sophisticated in terms of cable management. The adapter is mid-cable rather than being incorporated into the mains plug, so you have both the mains cable and the DC cable to negotiate, with only a tiny clip on the DC end to keep them organised.

Dell XPS 12 (2015) – Sound

Rather more expectedly, and far less disastrously, the sound quality on this tablet is pretty weak. The pair of stereo speakers that sit above the screen are reasonably clear at low volumes and have a noticeable stereo effect, but there’s very little oomph and overall volume.

Dell XPS 12 (2015) – Camera

The tablet features two cameras, an 8-megapixel rear-facing unit and a 5-megapixel front-facing one. Both are entirely adequate for basic snapping and video-calling duties – although, not surprisingly, neither competes with the latest and greatest sensors on smartphones.

Related: Dell XPS 13 (2015) review
Dell XPS 12 (2015)

Should I buy the Dell XPS 12 (2015)?

Dell almost aced the XPS 12 (2015). Its hybrid design was always going to be something of a niche, but within that space its excellent composition and build quality, along with class-leading screen, keyboard and trackpad, make for a technically impressive specimen.

However, the use of an Intel Core M processor results in modest performance, making it only really suitable for casual, rather than professional, use. In comparison, the Microsoft Surface Pro 4 packs in an Intel Core “i” processor and has the performance advantage to prove it.

But that’s not the worst of it. When it comes to battery life this is one of the worst tablets I’ve ever tested. At a push it might stretch to four hours, but in my tests it struggled to last even three. There may be a few folk out there who can see a use for a portable device that can last for only that time, but I’m struggling to think of one, especially since I wasn’t provided with a stylus to test its sketching potential.

And for all that you’ll be stumping up £1,299.

The one potential savour of this device is that it’s available in a version offering a lower resolution 1080p screen, less RAM and a more conventional 128GB SSD, rather than the whopping 500GB SSD here. Retailing for £899, it has the potential to be a reasonable buy, since there’s a good chance battery life will improve as a result of the lower resolution. Until I get the opportunity to test it, however, this can’t be confirmed.


Like so many devices before it, the Dell XPS 12 (2015) gets plenty right – but then blows it all with battery life. This is a hybrid with many class-leading qualities, but a three-hour battery life simply isn’t good enough.

We test every tablet we review thoroughly. We use industry standard tests to compare features properly and we use the tablet as our main device over the review period. We’ll always tell you what we find and we never, ever, accept money to review a product.

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Used as our main tablet for the review period

Reviewed using respected industry benchmarks

Ongoing real world testing

Tested with various games, apps and services

Trusted Score

rating-star rating-star rating-star rating-star rating-star

Score in detail

  • Performance 6
  • Keyboard 10
  • Design 8
  • Screen Quality 10
  • Build Quality 9
  • Value 7
  • Touchpad 10
  • Features 8
  • Battery Life 2

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