http://wiki.browncat.org/index.php/CentOS_5%E8%A8%AD%E5%AE%9A%E3%83%A1%E3%83%A2#CPU.E3.82.AF.E3.83.AD.E3.83.83.E3.82.AF.E3.81.AE.E3.82.B3.E3.83.B3.E3.83.88.E3.83.AD.E3.83.BC.E3.83.ABhttp://blog.browncat.org/2007/08/cpufreqselector.html