Despite Research In Motion's best efforts to silence them, questions about the battery life of its forthcoming PlayBook tablet have followed the company into the new year.

In a sequel to his original research note suggesting the PlayBook's battery life is "relatively poor" compared to rivals, Kaufman Bros. analyst Shaw Wu reiterates that claim, saying he would be "very surprised if PlayBook matches anywhere near the battery life of the iPad at 10 hours unless it uses a larger battery."

The reasons for this are threefold:

RIM&39's PlayBook

2. QNX, the operating system on which PlayBook is to run, wasn't designed for it. It was intended for devices drawing power from a wall socket or car battery, not mobile platforms whose power sources are necessarily limited by their own mobility.

3. RIM's implementation of power management is not as well-integrated as that of its rivals--particularly Apple, whose homegrown A4 system-on-chip enables the company to deliver superior battery life.

Obviously further work is needed to optimize the device's battery life' RIM admitted as much in its rebuttal to Wu's first note and, to be fair, this is a prerelease device--a work in progress. RIM still has a few months left yet to optimize the PlayBook's battery and get it to that "comparable" level it claims.

But even fully optimized, Wu doesn't see it matching the iPad.

"Our sources indicate that the best that PlayBook can probably deliver is six hours as offered by the Samsung Galaxy Tab, which is nearly half of that offered by iPad," he concludes. "And that is with significant re-engineering."

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