In my standard battery test, which I performed twice for accuracy, I got just over four hours each time, though Apple claims up to seven hours.

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In my standard battery test, where I play videos back to back with the screen at 75% brightness and both Wi-Fi and cellular connections turned on, the Tablet P lasted just 5 hours and 16 minutes, about half the battery life of an iPad.

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Our standard battery rundown test involves setting the brightness and volume to half, using 4G in a 75 percent or better signal area, enabling GPS and WiFi (not connected) and disabling Bluetooth while looping a video from a full charge until the battery is drained.

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On our standard Windows battery rundown test, in which we fix the display brightness and loop a video endlessly to exhaustion, the Surface Pro scored just three hours and 46 minutes, despite having a 42.5Wh battery a third larger than the 31.5Wh pack in the Surface RT.

FORBES: Links 6 Feb: Microsoft's Surface Pro Reviews. Not So Good Actually