First off thanks for the help. I have a opteron 1210 machine with kernel version 2.6.20-15-generic. I have not installed anything special for acpi. When I look at the /proc/acpi/processor/CPU0/info it has: processor id: 0 acpi id: 0 bus mastering control: yes power management: yes throttling control: no limit interface: no Now I believe that the opteron 1210 does support throttling, whats going on here? Do I need to patch or recompile my kernel? - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html