# Way to turn Hyperthreading ON vs OFF within windows 10 ??



## Carsomyr (Aug 28, 2017)

Question in title


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## Solaris17 (Aug 28, 2017)

You can probably do manual parking but no software way to do it.


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## dcf-joe (Aug 28, 2017)

Looks like Process Lasso is a "quasi" way to do this. It supposedly allows per-process customization of what cores a process can use.

There is a free version of this software. Here is a writeup from the developer:  https://bitsum.com/tips-and-tweaks/why-you-should-not-disable-hyper-threading-or-why-you-should/


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## Carsomyr (Aug 30, 2017)

is "disabling core parking" still a thing in windows 10?
with an i7 7700k?


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## eidairaman1 (Aug 30, 2017)

Look for core unparker, it is a registry trick, i used it on my 8350, should work in 10 too


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## EarthDog (Aug 30, 2017)

Carsomyr said:


> is "disabling core parking" still a thing in windows 10?
> with an i7 7700k?


It was for amd cpus. I dont recall it having any effect on intel.


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## eidairaman1 (Aug 30, 2017)

EarthDog said:


> It was for amd cpus. I dont recall it having any effect on intel.



There were 2 BD patches for 7, there is a utility called core unparker, it adjusts the registry, i presume some w7 entries relating to this are in 8 and 10.

In the days of XP hypthr didnt work, it was 7 that it really did, so its truly best to leave hyperthreading enabled today


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## Carsomyr (Sep 4, 2017)

eidairaman1 said:


> There were 2 BD patches for 7, there is a utility called core unparker, it adjusts the registry, i presume some w7 entries relating to this are in 8 and 10.
> 
> In the days of XP hypthr didnt work, it was 7 that it really did, so its truly best to leave hyperthreading enabled today



so..... does that mean if I don't touch the defaults settings in windows 10... Cores are being parked (therefore Hyper Threading not being used to its fullest) if I understood well? Correct?


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## FordGT90Concept (Sep 4, 2017)

Basically all it did was tell Windows not to assign threads to virtual cores.  Hyperthreading was still enabled but those logical cores would drop to 0% load.

In short, there's no way to completely disable Hyperthreading from an operating system.  It requires rebooting.


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## R0H1T (Sep 4, 2017)

Carsomyr said:


> so..... does that mean if I don't touch the defaults settings in windows 10... Cores are being parked (therefore Hyper Threading not being used to its fullest) if I understood well? Correct?


Core parking has nothing to do with HT. Windows just parks idle cores, when not in use, depending on system load.
You can adjust core parking behavior using this ~ https://sourceforge.net/projects/rightmark









Be advised that the utility does a lot more than just core parking!


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## Carsomyr (Sep 4, 2017)

so you recommend I use the utility to unpark the cores then?


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## Vayra86 (Sep 4, 2017)

The real question that hasn't been asked is:

why


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## R0H1T (Sep 4, 2017)

Carsomyr said:


> so you recommend I use the utility to unpark the cores then?


What exactly do you want to do with core parking?
Just set the power profile to high performance & min processor state to 100% if you don;t want Windows to park cores, *balanced* for well a balance of performance & power saving.
If you want HT to not work then get process lasso & use forced mode, the utility I linked to has fine grained performance tuning.
You can use it to set when/how the cores are parked & what algorithm the system uses for core parking & unparking. It basically sets parameter under which the processor loads or unloads cores, via core parking, for any number of tasks & then some.


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## Tatty_One (Sep 4, 2017)

I assume you can no longer do this in the Bios?  I used to with my old overclocked 920 in the summer to keep it a little cooler  but agree I don't see the point these days.


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## EarthDog (Sep 4, 2017)

You can do this in the bios...its the main place to do so. He just wants to disable in windows.


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## Carsomyr (Sep 4, 2017)

EarthDog said:


> You can do this in the bios...its the main place to do so. He just wants to disable in windows.



yeah I'm not trying to turn off HT. Just thought that if I do disable Core parking it would help stability in gaming and other tasks...
If Core Parking can be disabled simply by playing with the windows "power settings" why do I keep reading I need to use a "utility" to do the "unparking"?


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## Kursah (Sep 4, 2017)

Maybe the more important question to ask here is what stability issues you're having with "gaming and other tasks"? What details can you provide about those issues?

Maybe reviewing those we can help you find a solution, be it core parking or not.


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## MrGenius (Sep 4, 2017)

Utilities just automate and/or simplify the process. You can do all the tweaking manually if you prefer. Pretty much everything you need to know can be found here: https://bitsum.com/parkcontrol/. It's a lot of info and you'll want to read it all, and check out all the links for more.


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## EarthDog (Sep 4, 2017)

Core parking isnt really a concern in intel. I dont unserstamd why it would make things more stable. You barked up the wrong tree there.


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## Vayra86 (Sep 5, 2017)

Carsomyr said:


> yeah I'm not trying to turn off HT. Just thought that if I do disable Core parking it would help stability in gaming and other tasks...
> If Core Parking can be disabled simply by playing with the windows "power settings" why do I keep reading I need to use a "utility" to do the "unparking"?



You don't, forget about it, system doesn't become more stable with cores parked or unparked. A system is either stable or it is not, and when it is not, just disabling random bits of it makes absolutely zero sense.


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## Flaky (Sep 5, 2017)

One way to disable HT from within windows would be to: 
-dump UEFI configuration using AMI tools (or other, specific for UEFI implementation vendor - still, almost all consumer retail motherboards use AMI UEFI)
-find and change the value of HT setting in that configuration (it might require trial and error, or diffing two configurations - one with HT enabled and one with HT disabled)
-apply the modified configuration back to UEFI and doing a reboot

Of course this solution has to be adapted for every specific motherboard and UEFI version (offset of value to modify might change).
This exact method has been used to force DMI 3.0 on some laptops that were hard-locked to use DMI 2.0, what resulted in bottlenecking NVMe drive speeds.

Perfectly doable, but not that trivial


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