Power saving boost update for AMD multicore CPUs for Windows 7, Server 2008 R2

The local Advanced Programmable Interrupt Controller (APIC) timer is programmed to count even when it is not being used. Therefore, the local APIC timer runs in the C1 sleep state continuously at a constant rate regardless of performance state (P-state) transitions. This behavior causes the computer to consume unnecessary power. However, AMD processors support an […]

The local Advanced Programmable Interrupt Controller (APIC) timer is programmed to count even when it is not being used. Therefore, the local APIC timer runs in the C1 sleep state continuously at a constant rate regardless of performance state (P-state) transitions. This behavior causes the computer to consume unnecessary power. However, AMD processors support an inactive state for when the CPU APIC timer is not being used. Therefore, an AMD processor can enter the low-power C1E state. This low-power state saves up to an additional 10 percent in power. If your processor supports the C1E state, you can apply this update to allow for the potential power savings of the C1E sleep state, explained KB974090, download hotfix for Windows Vista SP2, of Windows Server 2008 SP2, of Windows 7, or of Windows Server 2008 R2.