Lenovo ThinkPad X1 Carbon (2015) Review: Back To Basics With Broadwell

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Battery Life

The Lenovo ThinkPad X1 Carbon is built for light-weight performance, but generally that presents a challenge in the area of battery life. However, with Intel's more efficient 14nm Broadwell CPU architecture on board, this machine still holds up well. Let's take a look.

Battery Eater Pro and Web Browsing Tests
Battery Life Testing
We run two tests to give you a sense of how long a system will last under light and heavy use. Our web browsing test is a light-use scenario in which we refresh a webpage every 3 - 5 minutes over a WiFi connection, until the battery is exhausted. The Battery Eater Pro test then gives the laptop a much heavier workload to simulate the kind of stress you might put on the machine with multiple resources engaged, including CPU, GPU, memory and storage.
Battery Web

Battery Eater Pro X1 Carbon

The 2015 ThinkPad X1 Carbon offers solid up-time as you can see, with the ability to last 8 hours and 21 untethered during our web browsing test. What's interesting is that it didn't last quite as long as last year's model, which beat out the newer 14nm Broadwell-powered machine by a hair's width 14 minute margin. This actually isn't all that surprising, considering the Core i5-5300U in the 2015 model has a base clock of 2.3GHz, while the i5-4200U in the 2014 X1 Carbon has a base of 1.6GHz. In addition, top Turbo speed differences of 2.9GHz for the 2015 X1 Carbon and 2.6GHz for last year's model, add to this variability, even though we're comparing a 14nm (2015) versus a 22nm (2014) CPU architecture here.

Under our heavy load Battery Eater test, the tables are reversed and the new X1 Carbon smokes last year's model by 48 minutes of extra up-time. However, the new X1 Carbon couldn't quite catch the more moderately clocked Dell and HP machines, powered by Core i5-5200U chips.  All told, the 2015 ThinkPad X1 Carbon offers very respectable battery life for a machine of its ultralight class.

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