Question I have X9SRi-F and changed following items in CPU power management in BIOS Power technology->custom C1e support->disabled Cpu c3 report->disabled Cpu c6 report->disabled Package c state limit->c0 however, when I run turbostat in RHEL6.4, I found the CPU cores still enter C6 state. Is it a BIOS problem? Answer For the linux OS that uses intel_idle driver, the c-states settings will not follow BIOS c-states settings but the driver instead. You can add kernel parameter "intel_idle.max_cstate=6" to grub.conf if you want the maximum core state to be C6. Or add "intel_idle.max_cstate=0" then the intel_idle will be disabled, and system will follow the BIOS setting when acpi_idle driver is available. Was this FAQ helpful? YES      NO Enter Comments Below: Note: Your comments/feedback should be limited to this FAQ only. For technical support, please send an email to support@supermicro.com.  Enter your email address below if you'd like technical support staff to reply:  Please type the Captcha (no space) 4 R F E FAQ Stats FAQ ID Related Category / Keyword Date Posted Code 17520 BIOS: - BIOS Setting Operating Systems: - Linux OS 11/25/13     Print Answer