ACPI with AMD64

[Thimo Eichstaedt <abc@digithi.de>]

Hi folks,

I have an Athlon AMD 64 3000 MHz and want to use its powersaving 
futures. Therefore I am using PowerNow with the powernow_k8 module. 
This is working great.
Additionally it should be possible to profit from the power states of 
the processor (C1...C8). But the ACPI module tells me that only C1 is availabe:

Modules loaded: processor, powernow_k8, cpufreq_userspace
dmesg output when loading processor.ko module:
...
ACPI: CPU0 (power states: C1[C1])
...

cat /proc/acpi/processor/CPU0/power:
active state:            C1
max_cstate:              C8
bus master activity:     00000000
states:
   *C1:                  type[C1] promotion[--] demotion[--] 
latency[000] usage[03559864]

 cat /proc/acpi/processor/CPU0/throttling
<not supported>

Is this correct or what have I done wrong ? Can anybody with a AMD64 
processor perhaps post its proc output ?

Thanks
  Thimo