Microsoft Patches Core Duo Battery Bug

Microsoft on Tuesday posted a Windows XP patch to fix a power drain problem for notebooks running Intel's Core Duo processor. The issue, which Microsoft had kept quiet since summer 2005, was made public in February.

Core Duo-powered portables quickly drained their batteries, Microsoft said in a support document also posted Tuesday, because the USB 2.0 driver kept the CPU from entering "the deeper ACPI processor idle sleep states, or 'C-states.'

"C-states save power when the processor is not busy. These states range from 'C0' to 'C3' or 'C4.' Typically, an idle portable computer uses the C3 and C4 states to preserve battery power. If an idle portable computer cannot enter or maintain the C3 or C4 states, the battery power drains more quickly."

The Windows XP SP2 patch can be downloaded from Microsoft's Web site. Users must be using a legitimate copy of Windows to retrieve the fix.