Disable CPU idle

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deama
Posts: 370
Joined: 07 Aug 2019, 12:00

Disable CPU idle

Post by deama » 25 Apr 2023, 03:44

Found a tweak to disable CPU idle so it's always at 100%, helps with consistency and input lag:
phpBB [video]


Despite what he says in the video, it doesn't make the temps go up by much for me, only +5 degrees at most on system "idle".
I do get about +30W power usage on system "idle" now too, but not much of a difference for me, was 50W Before now is 75-80W.

I'm on 7950x3dv. Also, I have SMT disabled, maybe that helps even more with the temps.

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Tiberiusmoon
Posts: 149
Joined: 10 Feb 2023, 05:05

Re: Disable CPU idle

Post by Tiberiusmoon » 25 Apr 2023, 05:56


sherifmagdy32
Posts: 125
Joined: 08 Jan 2022, 23:43

Re: Disable CPU idle

Post by sherifmagdy32 » 25 Apr 2023, 07:05

Definitely wouldn't recommend disabling idle it uses a lot of power and degrades the silicon so fast the cpu usually last around 2 years then the performance takes so huge hit you will need to buy a new system
i saw this happen to a ton of fortnite pro's because all the tweakers the first thing they do is disable idle
the smart way to use this would be to use process lasso performance mode and switch to your performance power plan with idle disabled when it detects the games running you can control what games this give you the best from both worlds
i actually do use this myself.

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Tiberiusmoon
Posts: 149
Joined: 10 Feb 2023, 05:05

Re: Disable CPU idle

Post by Tiberiusmoon » 25 Apr 2023, 07:38

sherifmagdy32 wrote:
25 Apr 2023, 07:05
Definitely wouldn't recommend disabling idle it uses a lot of power and degrades the silicon so fast the cpu usually last around 2 years then the performance takes so huge hit you will need to buy a new system
i saw this happen to a ton of fortnite pro's because all the tweakers the first thing they do is disable idle
the smart way to use this would be to use process lasso performance mode and switch to your performance power plan with idle disabled when it detects the games running you can control what games this give you the best from both worlds
i actually do use this myself.
^This.
My wattage usage is doubled when disabling Idle so I use lasso to enable ultimate power plan for specific games.
For GPU its a matter of setting your power plan to normal globally then enable performance when a game is running.

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F1zus
Posts: 155
Joined: 07 Nov 2022, 17:59

Re: Disable CPU idle

Post by F1zus » 25 Apr 2023, 08:07

I did a lot of tests with my amd 5600x and cpu idle state. I came to the conclusion that with the CPU idle disabled, the game is not so smooth, the enemies teleported near me. Yes, the mouse felt sharper. My friend expressed the same opinion, he tested it on 10400f.

Unreazz
Posts: 175
Joined: 30 Dec 2019, 06:45

Re: Disable CPU idle

Post by Unreazz » 26 Apr 2023, 13:24

i would not reccomend this, if you have hyperthreading on

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Espionage724
Posts: 8
Joined: 13 Jul 2022, 15:45

Re: Disable CPU idle

Post by Espionage724 » 25 May 2024, 15:04

Disabling CPU idle states entirely is silly if you properly turn off other power management, and as noted breaks HT/SMT on some platforms. The concept alone has useless code looping/running in-place of idle along with wasting CPU headroom, and never-mind the idle temps and power usage. This might have been tolerable on single-core P4s.

On Linux I noticed using the halt function didn't seem to have negative effects, and sounded better on-paper :p mwait sounded slower, and disabling cpuidle entirely runs slower due to having to execute some loop (and is even suggested not to do so for performance purposes).

I wonder if Windows has different implementations for cpuidle and if they can be selected?

Also there was one interesting tweak on the first video about disabling Threaded DPCs. Here's a one-liner for anyone else curious:

Code: Select all

reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\kernel" /v "ThreadDpcEnable" /t REG_DWORD /d "0" /f
https://learn.microsoft.com/en-us/windo ... eaded-dpcs

Thatweirdinputlag
Posts: 322
Joined: 27 Aug 2021, 14:09

Re: Disable CPU idle

Post by Thatweirdinputlag » 25 May 2024, 15:49

deama wrote:
25 Apr 2023, 03:44
Found a tweak to disable CPU idle so it's always at 100%, helps with consistency and input lag:
phpBB [video]


Despite what he says in the video, it doesn't make the temps go up by much for me, only +5 degrees at most on system "idle".
I do get about +30W power usage on system "idle" now too, but not much of a difference for me, was 50W Before now is 75-80W.

I'm on 7950x3dv. Also, I have SMT disabled, maybe that helps even more with the temps.
We've talked about this before, and I surely am against this tweek in particular. It will burn up your CPU, will force it to degrade way faster than how it normally would, not to mention the amount of extra watts that your system would use and the heat that it will produce. It's literally not worth it! Even on the graph itself, the variations between CPU Idle and CPU Idle Disabled is barely within the range of 0.3-0.4ms. Granted he has an optimized PC, but the idea is still the same.
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