Some systems with AMD Phenom II and AMD Athlon II processors do not properly change frequency on all logical cores under RHEL 5

Issue

On some systems, the default CPU frequency scaling initialization method  used by the powernow-k8 frequency driver module, and the ACPI data provided by BIOS, are not compatible with each other. Changing CPU clock speed on such systems reports to change properly but testing reveals that only cpu0 has a change in frequency. This results in limited actual power saving.