by jiml8 » Jul 18th, '13, 18:54
For what it is worth, I am running an Asus Sabertooth 990FX R2 motherboard with an AMD Phenom-II 955 quad-core processor. This is the first Linux system I have run where I enabled the AMD "Cool n Quiet" feature and left it on; in all previous systems, I had noticed performance impacts that were sufficiently severe to cause me to disable the feature in BIOS and not run any power management in the system.
My system is set to "ondemand" and I have noticed no performance issues. In fact, I am continually monitoring CPU temperatures and clocks, and I find the behavior of the system to be excellent. I do at some times experience "stuttering" of the KDE interface, but this seems related to a memory leak in X as opposed to anything else, and clearly is dependent upon how long KDE and X have been up and running.