Research In Motion fired back after an analyst cited unnamed sources that said the battery life of its Playbook tablet was less than that of its competitors.

An analyst from Kaufman Brothers, Shaw Wu, wrote a note to investors that said battery life was only a few hours and compared unfavorably to that of Samsung's Galaxy and the iPad. RIM issued a statement that said the testing would have been done on pre-beta versions of the tablet that didn't have power management software installed.

RIM's co-CEO Jim Balsillie said at a conference in October that the battery was rated at 5,300 milliamp-hours. The Samsung Galaxy Tab's battery has a rating of 4,000 mAh, while the Dell Streak comes in at about 1,530 mAh.

Samsung claims that the battery can play a movie for seven hours. Unlike the Samsung, Apple or RIM tablets, the Dell battery is removable and the company says it will work for nearly 10 hours of talk time. Apple puts the iPad battery life at about 10 hours also. It is not clear under what conditions any of these devices were tested.

Apple has sold more than 7 million iPads since launching the device in April, and according to some analyses has more than 90 percent of the tablet market.