I've managed to unlock ASPM settings in the BIOS, I did get all peripherals showing as ASPM enabled, this saved about 2 watts on idle, however the CPU was still not entering any sort of C state, it was saying almost 100% in C3 in pfSense but this resulted in no power savings. I could switch C-states on and off and see absolutely no change in power consumption. Like I've said I have an older i7 box with 6 Ethernet ports which with no difficulty at all is idling at ~4 watts, practically cold to the touch and just runs without issue, never ever crashed, so these appliances are easily able to run at very low power. It is very annoying that a newer more efficient processor in the same form factor is drawing at idle almost 3 times as much power, and even uses more power when it needs to ramp up. Its funny how all these N100 type appliances from China are all idling around the 11-12 watt.You're seeing C states on the cores, but none on the entire package. I think this is a common issue on the N series though we can't always prove if it's the cpu, board or bios.
When devices have had bioses with working ASPM and related settings, it has been possible to enable things like PCIe & sata power saving which has allowed package C states and reduced the idle wattage. That can be a magical black art though since any peripheral or circuit (or bios/driver element) that does not correctly handle the power down and restart will lead to crashes. We're luckiest when the element says "NO", since that won't introduce crashes. Some of the cwwk bioses have had the ASPM controls, but others have it blocked off because - we assume - too many people were setting it too aggressively for the hardware and creating failures and support calls.
Eg. NAS motherboards with the JMB sata chips struggle a lot as they don't appear to support ASPM well, or possibly at all. The purple/K board with ASM1166 instead was invented to avoid that issue but first (& some? later?) bioses still hid the settings.
It's also a clear thing that most N series devices fail to power down some sections of the motherboard leading to high-ish idle watts. That could just be package c states but feels like it's weak design in the bios/uefi drivers or actual hardware which keeps some elements at full power (eg. Network, SATA, usb).
I do wonder if the same might even be true of some branded NUCs & motherboards, but as they usually have 1x1gb network, 1-2 sata etc it may not show. It is clear that the earlier generations were better overall at this - which is sad.
I'm thinking of getting a Protectli VP6630 to get something branded with hopefully some support, would I see the same issues? In my case I will just put in a SATA drive which shouldn't really upset things.
There is also this interesting article here which suggests its a problem with all modern Intel processors: The Curse of Intel 12th Gen C-States