Intel Core Duo USB Issue: A Mischaracterized Bug

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Will plugging a USB 2.0 device into your notebook kill your battery life? Is Intel's new Core Duo processor the victim.

Basically if you have a USB 2.0 device plugged in to a computer running Windows XP SP2, your processor will not be able to enter lower power states (e.g. C3, C4 or Deep C4 in the case of Core Duo). The problem is that if a very power efficient CPU is prevented from going into its C3 or C4 states, then it?s consuming a lot more power than it needs to be. It?s particularly bad because the problem could exist just by having any USB 2.0 device plugged in, even if you?re not using the device.

Keep in mind that Microsoft's description of the issue does not place the blame on Intel's Core Duo processor, and instead implies that it would exist on all platforms regardless of CPU. Later on in this article we'll attempt to find out whether this is indeed a universal problem or something that only really impacts Core Duo.

AnandTech