Lenovo ThinkPad L420 Battery Life, Heat and Noise

June 2, 2011 by Charles P. Jefferies Reads (163,990)
Editor's Rating

Ratings Breakdown (1-10)

    • Software & Support
    • 8
    • Upgrade Capabilities
    • 7
    • Usability
    • 6
    • Design
    • 8
    • Performance
    • 7
    • Features
    • 7
    • Price/Value Rating
    • 6
    • Total Score:
    • 7.00
    • Rating 1 to 10, top score 10

Heat and Noise
The L420 has a single fan that exhausts out the left side of the chassis. It is always on and audible, however has no annoying pitch; it mostly sounds like a rush of air. Even under full load, the fan hardly gets louder. It would be nice if the fan turned off when the notebook idles.

The surface of the notebook remains room temperature; under full load, the only warm spot on the notebook is the bottom of the chassis under the fan intake. Overall, the L420 has a good cooling solution.

Battery Life
The L420 has a modest 6-cell 57Wh battery. I measured four hours, 36 minutes of life during our standard battery rundown test (Windows 7 Balanced power profile, 70% screen brightness, wireless active, and refreshing a web page every 60 seconds). This is less than I expected; I was looking for a time well north of five hours.

Battery life test results (higher scores mean better battery life):

The Lenovo ThinkPad L420 is an above-average offering in the value business notebook segment. It succeeds in barely enough areas to get our recommendation, however. Highlights first: very good build quality, an excellent keyboard and touchpad, a good selection of input/output ports, and good overall performance. Now for the downsides; the first is battery life. Four and a half hours is average at best; ideally we were looking for another hour. Secondly, the 1366×768 screen resolution is too low for office productivity and makes multitasking difficult. Lastly, the $969 asking price is a bit high; Lenovo should either knock $100 off the price or include at least a two-year warranty standard.

In the end, the Lenovo ThinkPad L420 is a very well-built machine and meets most of our expectations.


  • Very good build quality
  • Excellent keyboard and touchpad
  • Good selection of ports


  • Average battery life
  • Low screen resolution
  • Only 1-year warranty standard



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