I think this is a better link for information concerning the subject matter: http://www.hardwaresecrets.com/article/611/1
Basically, since you are only using C1E this will be as far as you will go with power management. If you had Speedstep enabled you would have C1 to CX depending on the supported states of the processor.
I never really used power management till Vista and the Core 2 Duo. During my usage of Athlon 64's I preferred not to use CnQ at all. There were issues with it, even then. Not once did I think to myself, this is operating slowly with Speedstep though.