Should i leave Global C-States Disabled by default?

[benjji1]

Hi, I was looking for answers online but there seems to be some conflicting answers on whether or not to use C-states, some say that disabling it reduces input lag/latency and stutters, while others say it doesnt affect performance and only affects power draw and thermals and thus should be left on auto or enabled. ive also seen it recommended to leave on for my CPU (5800x3d) but for my motherboard (MSI B450 Tomahawk max, latest BIOS) it leaves it disabled by default, so im just wondering if i should stop worrying about it and just leave it alone as default.

I did try to test with and without quickly on ESO and moving the camera around seems to feel snappier, and less floaty. Would that be considered latency or input lag? or is it placebo and my brain tricking me into believing that it seems smoother? Sorry if that sounds like a dumb question and/or a difficult one without personally seeing for yourself. I just need a another opinion telling me yes or no.

[MatrixQW]

There are two things to consider, performance (fps) and latency (responsiveness).
C-States disabled also disables CPU turbo boost on non K CPUs or on K series CPUs with a non Z series board. You will get less performance.
C-States enabled can cause stutters and latency (microseconds mostly) in specific cases.

With HWInfo64 you can log the cores usage and C-State Residency to see if they are in C0 or keep transitioning from C7 when playing a game.
You can disable C-States only for 'High Performance' power plan and have them enabled for 'Balanced'. Use the app powersettingsexplorer (set Processor idle demote/promote threshold to 100 and unhide them).

Set 'High Performance' powerplan, run the game and while you're playing and after you get used to the feeling of the mouse, alt+tab and enable C-States again in energy options (40% and 60% are default).
This way you can instantly tell if there is actually a noticeable difference in responsiveness, just don't force yourself believing there is.

Set this in bios for stability:
- CPU C-States: Enabled, not auto (and disable C1E state, this one causes issues)
- CPU Core Ratio: Sync All Cores

[benjji1]

There are two things to consider, performance (fps) and latency (responsiveness).
C-States disabled also disables CPU turbo boost on non K CPUs or on K series CPUs with a non Z series board. You will get less performance.
C-States enabled can cause stutters and latency (microseconds mostly) in specific cases.

With HWInfo64 you can log the cores usage and C-State Residency to see if they are in C0 or keep transitioning from C7 when playing a game.
You can disable C-States only for 'High Performance' power plan and have them enabled for 'Balanced'. Use the app powersettingsexplorer (set Processor idle demote/promote threshold to 100 and unhide them).

Set 'High Performance' powerplan, run the game and while you're playing and after you get used to the feeling of the mouse, alt+tab and enable C-States again in energy options (40% and 60% are default).
This way you can instantly tell if there is actually a noticeable difference in responsiveness, just don't force yourself believing there is.

Set this in bios for stability:
- CPU C-States: Enabled, not auto (and disable C1E state, this one causes issues)
- CPU Core Ratio: Sync All Cores

Thanks alot for the reply, its helped me understand c-states better. Unfortunately i couldnt find the BIOS setting for the C1E state, although i dont believe that really matters since i dont even think my processor uses that state. (i checked hwinfo64 and only saw C0,C1 and C6.) and as for the power plan i could only find the Demote threshold, not the promote. does that matter? i also saw a setting called "Processor Idle Disable" which says it controls idle states, could i not just disable that setting instead? i could then just swap to that power plan whenever i decide to play games.

[benjji1]

nevermind, i managed to find the idle promote setting and applied it to my high performance power plan, thanks alot for letting me know about that setting as otherwise i wouldve been torn on whether or not i should restart my entire pc just to check the setting, ill test this out on my next couple times playing games and see if i could tell the difference. and as for the processor idle, i disabled that and all it did was force my CPU to boost all cores,so just renabled it and left it hidden.

[MatrixQW]

C-States are a power saving for CPU. Different states shut down more parts of the cpu. That's all it does.
C1E (Enhanced Halt) does not appear in HWInfo64 but if your CPU supports it (probably does) it will be used.

i also saw a setting called "Processor Idle Disable" which says it controls idle states, could i not just disable that setting instead?

Don't do this! It will increase your cpu temperature by alot and degrade it's life quicker for nothing.
What this does is keep all cores at C0 state. Keep this setting enabled and hide it from power plan.
The 'Processor idle demote/promote threshold' = 100 effectively disables C-States and keeps cores at C1 and can instantly go to C0 without latency penalty. With this your cores should be in C1 in idle.

This is C1E on my bios. See if you have a third option in C-States instead of just enabled/disabled to custom or something.
If I don't disable C1E, CPU is never 3.9GHz steady, keeps fluctuating. Try to find it and disable it.
And If I don't set CPU Core Ratio to 'Sync All Cores', CPU turbo boost only reaches 3.7GHz.
I have a K-CPU and a Z-Board so I can actually have C-States disabled and turbo boost working. Lucky me.

[JimCarry]

So if i have i5 6600 c-state should be enabled ?

I have disabled all c-state related options via scewin.

[benjji1]

C1E (Enhanced Halt) does not appear in HWInfo64 but if your CPU supports it (probably does) it will be used.

I dont think my CPU actually uses this state,I've tried to find anything that says the 5800x3d uses it but couldn't find anything. I also tried using throttlestop to see if its enabled but that doesnt work for the 5800x3d either. couldnt see any option that could refer to C1E in my BIOS aswell,neither do i have the "Sync all Cores" option in my BIOS. i think its just because how locked-down the 5800x3d is when it comes to overclocking, and/or my motherboards BIOS not having the feature.

[F1zus]

C-States are a power saving for CPU. Different states shut down more parts of the cpu. That's all it does.
C1E (Enhanced Halt) does not appear in HWInfo64 but if your CPU supports it (probabl

i also s
Don't do this! It will increase your cpu temperature by alot and degrade it's life quicker for nothing.
What this does is keep all cores at C0 state. Keep this setting enabled and hide it from power plan.
The 'Processor idle demote/promote threshold' = 100 effectively disables C-States and keeps cores at C1 and can instantly go to C0 without latency penalty. With this your cores should be in C1 in idle.

This is C1E on my bios. See if you have a third option in C-States instead of just enabled/disabled to custom or something.
If I don't disable C1E, CPU is never 3.9GHz steady, keeps fluctuating. Try to find it and disable it.
And If I don't set CPU Core Ratio to 'Sync All Cores', CPU turbo boost only reaches 3.7GHz.
I have a K-CPU and a Z-Board so I can actually have C-States disabled and turbo boost working. Lucky me.

"promote threshold" = 1, as Microsoft writes. The higher the number, the slower the processor performance increases.

[JimCarry]

C-States are a power saving for CPU. Different states shut down more parts of the cpu. That's all it does.
C1E (Enhanced Halt) does not appear in HWInfo64 but if your CPU supports it (probabl

i also s
Don't do this! It will increase your cpu temperature by alot and degrade it's life quicker for nothing.
What this does is keep all cores at C0 state. Keep this setting enabled and hide it from power plan.
The 'Processor idle demote/promote threshold' = 100 effectively disables C-States and keeps cores at C1 and can instantly go to C0 without latency penalty. With this your cores should be in C1 in idle.

This is C1E on my bios. See if you have a third option in C-States instead of just enabled/disabled to custom or something.
If I don't disable C1E, CPU is never 3.9GHz steady, keeps fluctuating. Try to find it and disable it.
And If I don't set CPU Core Ratio to 'Sync All Cores', CPU turbo boost only reaches 3.7GHz.
I have a K-CPU and a Z-Board so I can actually have C-States disabled and turbo boost working. Lucky me.

"promote threshold" = 1, as Microsoft writes. The higher the number, the slower the processor performance increases.

I dont get it ? i should put promote / demote to 100 or to 1?

[MatrixQW]

So if i have i5 6600 c-state should be enabled ?

If you want your cpu to use turbo boost then yes, they need to be enabled.

I dont get it ? i should put promote / demote to 100 or to 1?

This is the % the cpu must achieve to change states. To fully disable C-States you need to set both demote and promote to 100, not 1.
Leave HWinfo64 sensors window open, open the power plan options, change demote/promote and hit apply.
You will see that all C-State Residency will instantly be 0.0% except 'Core C0 Residency' with small values since cores will be in C1.

If you disable C-States through power plan, you might as well change 'Processor performance time check interval [4d2b0152-7d5c-498b-88e2-34345392a2c5]' to the highest value (5000), since there is nothing to check anymore.
This will save cpu cycles, instead of checking every 15ms (default) you can set it to every 5000ms.