Turbo Core and Turbo Boost interact with a system's power saving features, which clock down individual cores or the whole processor and decrease the voltage to reduce power consumption when a system is idle. Herein lies the problem with AMD's new processors in current Linux kernels: when their "Cool'n'Quiet" feature is enabled, Turbo Core processors no longer step up to their nominal speed, but operate at a slightly slower frequency.
The simplest workaround is to disable the "Cool'n'Quiet" feature. This requires users to fully disable the function in the board's BIOS set-up, or to instruct the kernel not to adapt clock speeds via cpufreq – the Fedora Linux distribution allows users to do this by stopping the "cpuspeed" daemon, while other distributions require users to blacklist the powernow-k8 kernel module, which is responsible for cpufreq in modern AMD CPUs. However, disabling the power saving features can increase an idle system's power consumption by 10 to 20 watts.
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