Temperature and cooling

Just before looking at the charging speed, we went on to deplete the battery by running a very intensive CPU test called Prime 95. It will push all cores to 100% utilization and will heat up to the point where the thermal throttling will kick and and stabilize the temperature of the system to avoid a critical crash. We control the temperature with the Core Temp utility. The Carbon X1 won’t burn your lap anytime soon.


It is possible to force the laptop to push the limits by clicking on the battery icon and selecting the faster performance mode, which favors speed at the expense of battery life. Our ambient temperature at the time of testing was 23C.

  • “Best Performance” caps the CPU utilization to a sustained 80%
  • “Better performance” allows the CPU to work as fast as the temperature will allow
    • a sustained ~95% CPU usage in practice, with the CPU temperature at 67C to 69C (37C while idle)

We also took some infrared shots and left the power supply visible as a reference. It had a surface temperature of 45C. The 36C hottest point on the X1 Carbon keyboard is visible in the image below, while the palm area was around 27C. In the back, the the edge of the laptop (near the screen) experienced a temperature of 38C, just 1C above body temperature.

The Lenovo X1 Carbon cooling system works very well, especially when considering that it is relatively quiet, more so than other ultra-compact laptops such as the formidable Matebook X Pro, for example.

Overall product rating: 9/10

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