5/18 - Microsoft Fixes Windows XP SP2 Laptop Battery Drain Problem

2/18 - Microsoft is hard at work fixing a driver bug that affects laptop computers and battery life every time a USB 2 device is connected to a laptop running Windows XP with Service Pack 2. Many notebooks ship with integrated USB 2 devices, so these computers are immediately affected. Laptops can lose over an hour of battery life. A "28% reduction in battery life for simply plugging in a USB 2.0 device is beyond ridiculous".

Microsoft has known about the bug for at least a half year. Nevertheless, so long as the public did not know about the bug, it appears that it was not a top priority. If anyone has a vested interest in fixing this bug, that would be Intel. Not even Intel was able to hurry Microsoft on this one.

5/19 - Microsoft power drain bug fix may only benefit Core Duo notebooks

Then something strange happened. The folks at Tom's Hardware discovered that something was wrong with the battery life of certain systems under certain conditions. Since the problem was discovered on one of the new Core Duo notebooks, it was naturally thought to be a Core Duo or Core Duo chipset problem. Notebook manufacturers complained that the problem "prevented their systems from achieving the goal of four to five hours of battery life".

Intel, however, insisted that the problem was not specific to Core Duo or the Centrino Duo platform. The code name for Centrino Duo was Napa. Intel declared, "This is an issue that is not specific to Napa. We expect this problem to occur on any system".

Subsequent empirical investigations confirmed that the problem was present, even more pronounced, on other platforms. The bug prevents laptops from entering lower power states, also known as C states. The "problem would exist on any system that spent any time in C3 or lower power states".

So the problem has been known about for some time, without anything tangible being down about it. The collective number of lost computing hours must be enormous.

With all of the publicity surrounding this bug, Microsoft has come forth, accepted responsibility, and promised a permanent solution. It won't be easy, because a permanent solution requires a BIOS upgrade, in addition to a patch to the registry. Not just one or the other.

A registry patch, in fact, already exists. But it is manual, so you risk screwing up your computer.

Plus, it's not permanent. Once a system comes out of Stand By, the old bug resumes its effectiveness and will not let the processor enter into a lower power state. While "applying the fix gives you back the vast majority of your lost battery life, it won't remain active coming out of suspend".

So the advice for the moment is to wait. The company recommends that customers "wait for the patch as well as a BIOS update, both of which are currently under evaluation in Microsoft's labs".