c3 states in core duo

I've had my nc6400 for about a week now and i'm loving every bit of it.

one question i have about the notebook is the EIST (enhanced intel speed step technology) functionality.

On battery, both cores enter into the c3 power state when the cores are idle.

When i plug the notebook for ac power, though, the max power state that the cores will enter is c2. I'm not too concerned with the issue as the c-states are not that important while on ac power (benefit of lower c-states is prolonged battery life). I'm just wondering if this is a phenomenon (or glitch) that's attributed to the nc6400 line (or maybe just my notebook). I had a dv2000t before this and it always entered the c3 state regardless if it's on battery or not.

I checked the power states via perfmon and the intel thermal analysis tool and both show that both cores do not enter the c3 state while on ac power.

Any ideas or thoughts?

oh, specs:
core duo t2400
latest bios (f.08)
win xp pro

 

I'll try to find the link in the HP business support forums, but when the nc8430 was having some fan issues a few users said the same exact thing was seen on the nc8430. C2 or higher only when on AC.

HP's reply was that it was Intel's recommendation to do things that way and they would not change it despite customer request. Understandable, as Intel knows how to best handle their chips. The Home HP (dv2000 the like) probably decided to do it anyway, but HP business is always going to go by the book.