Critical_ writes "Tom's Hardware recently discovered a bug in Microsoft's ACPI driver implementation under Windows XP SP2 that causes a loss of more than one hour of battery time when connecting any USB 2.0 device to an Intel Core Duo based system. Apparently Microsoft, Intel and ODMs have known of this problem under a confidentiality agreement since July 12, 2005 via (a still private) Knowledge Base article KB899179. The bug lies in the asynchronous scheduler component inadvertently being left running causing Windows' internal task scheduler (ITS) to treat it as a running process involving the attached device. This in turn prevents the ITS from powering down the processor into one of the ACPI sleep states causing the system to use more battery power. At this time there seems to be no fix. Strangely, single-core systems and AMD systems are not affected. This leads one to wonder if it is truely a software problem or if there a much larger hardware problem that may affect Core Duo equipped Apple systems."