Usually, there's an inverse relationship between laptop screen resolution and battery life. The more pixels your notebook display has, the more power it uses and the sooner it conks out. However, Lenovo's 12.5-inch ThinkPad X260 stands out because it got the same epic endurance with both its default 1366 x 768 panel and its higher-resolution, 1920 x 1080 screen.

We ran both ThinkPad X260 configurations through our Laptop Battery Test, which involves continuous surfing over Wi-Fi. The model with the 1366 x 768 screen lasted 17 hours and 14 minutes on our battery test with a 6-cell battery on board and 8 hours and 16 minutes with a 3-cell unit. A similarly-configured X260 with a 1080p screen lasted 17:23 and 8:26 respectively. The higher-resolution system actually lasted 9 to 10 minutes longer, though that delta is within our test's margin of error.

With either screen on board, the ThinkPad X260 is the longest-lasting laptop on the market today, provided that you use the 6-cell battery. The ThinkPad's 17-hour endurance is more than double the ultraportable laptop category average of 7 hours and 55 minutes. Unfortunately, the 8 hours it gets with the smaller battery is just slightly above average.

MORE: Which ThinkPad is Right For You?

If you purchase the ThinkPad X260 from Lenovo.com, it costs just $150 to upgrade to the 1080p screen and a mere $15 extra to move from the 3-cell battery up to the high-capacity, 6-cell unit. Don't even consider buying the laptop without both of those options.

Though neither X260 screen is particularly vibrant, the 1080p panel is much brighter. The 1920 x 1080 display registered a very-strong 324 nits on our light meter, much better than the 303-nit category average, while the base-model managed a dim 185 nits. Unfortunately, the 1366 screen covers just 67 percent of the sRGB gamut and the 1080p can only reproduce 65 percent. The average ultraportable manages 88.6 percent, which allows for a lot more colors.

ThinkPad X260 Display: Test Results Benchmark 1366 x 768 panel 1920 x 1080 panel Brightness 185 nits 324 nits Color Gamut (sRGB) 67 percent 65 percent Color Accuracy (Delta e) 3.8 2.54

Even if both displays were equally bright, we'd still recommend the 1080p panel, because of the added screen real estate. The high-res panel has 40 percent more vertical pixels, which is enough to see several more lines of text in a document or on a web page. With 1920 horizontal pixels, you can reasonably split the screen between two windows, something that's not pleasant with only 1366 of them.

If you're looking for a productivity-centric business laptop, the ThinkPad X260 should be near the top of your shopping list. In addition to its industry-leading battery life, the lightweight laptop sports a comfortable keyboard, lightweight MIL-SPEC-tested chassis, solid performance and plenty of ports. To learn more about Lenovo's laptop, check out our full review.