Difference between core C-states and package C-states?

[Fandabidozi]

Does anyone know what the difference between the two are? I have manually set my core c-states to C3 as my psu is not compatible with C6 & C7 states when waking from sleep mode. Also I have instability issues with my overclock if the core voltage drops to 0v.

I also have another setting in my BIOS which is "Package c-state limit". By default this is set at auto which disables the package c-sates. If I set it to a limit of C3 I can see in HWiNOF64 that the package and core c-states are completely separate from each other. My cores run at either C0 or C3 state and my package can run at either C2 or C3 state. The C3 state in the core and the package show completely different values so I know they aren't the same thing.

I have tried to do some research and found a little information on the subject. It is my understanding that the core C states are purely about power states on the cores of the CPU where as package C-states are an additional attempt to save even more power on various other components on the motherboard.

I would appreciate it if someone could confirm if my understanding is correct or if I am wrong in my thinking?

Thanks for any input.

[Bad 💀 Motha]

http://letmegooglethat.com/?q=explain+c-state+power+saving

[Snow]

Originally posted by Bad 💀 Motha:

http://letmegooglethat.com/?q=explain+c-state+power+saving

Yeah, if only.

Originally posted by archie130979:

package C-states are an additional attempt to save even more power on various other components on the motherboard.

Nah, this has nothing to do with motherboard. See, a modern CPU consists of a bunch of various things, not just cores. There are various sensors, iGPU, shared L3 cache, memory controller and a lot of other stuff I don't have a single clue about. So, from what I understand, by making the package go into C-state you effectively putting all that extra stuff to idle mode as well, essentially turning off the whole CPU, thus saving more power, than if you'd only put cores to C-state.

[Fandabidozi]

Originally posted by Bad 💀 Motha:

http://letmegooglethat.com/?q=explain+c-state+power+saving

I had already run a search and while I found plenty on C-states, mostly referred to core C-states and there doesn't seem to be anything very clear about what package C-states are.

Originally posted by Snow:

Originally posted by Bad 💀 Motha:

http://letmegooglethat.com/?q=explain+c-state+power+saving

Yeah, if only.

Originally posted by archie130979:

package C-states are an additional attempt to save even more power on various other components on the motherboard.

Nah, this has nothing to do with motherboard. See, a modern CPU consists of a bunch of various things, not just cores. There are various sensors, iGPU, shared L3 cache, memory controller and a lot of other stuff I don't have a single clue about. So, from what I understand, by making the package go into C-state you effectively putting all that extra stuff to idle mode as well, essentially turning off the whole CPU, thus saving more power, than if you'd only put cores to C-state.

Thanks for the information. I knew it was different from core C-states but was just unsure to what it actually was. I run both core and package C-states at a maximum of C3. Anything higher and I have stability issues which are mainly caused by my overclock as it will run fine at stock settings with C7-state. Also as mentioned before after checking on the Corsair website my PSU although they say it would probably be okay, it was not designed to use C6/C7 in sleep mode (which I use alot) as it can have issues waking up if the core voltage has dropped to 0v.

[a7dfj8aerj]

During the CPU C3 State, the CPU clock generator is turned off.
During the CPU C6 State, the power to all cache is turned off.
Taken from bios manual

[Furry Chemistry]

From here[metebalci.com]:

... package C-states (PC-states). The reason for PC-states is there are other (shared) components in the processor that can also be powered down after all cores using them are powered down (e.g. the shared cache).

"Package" means the entire CPU as a package.