# Quick Question: Over/Underclocking is it possible?



## zombiegator (May 30, 2016)

Hello, just like the title says I want to know if over clocking or more specifically under clocking is possible. The reason being is if I want my phone to save some extra battery I would like to be able to under clock it, I am not a performance app user so I think receiving and sending text and calls would be fine with an under clocked CPU, I was trying to find if anyone had answered this but I couldn't find anything useful. I just want an opinion from the experts! Thanks so much!


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## augustinionut (May 30, 2016)

I found some registry keys with processor freq. Tonight will edit post.


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## zombiegator (May 30, 2016)

augustinionut said:


> I found some registry keys with processor freq. Tonight will edit post.

Click to collapse





Thank I would be very curious to find out what happens! I would love it if I could under clock a little to save some battery!


Sent from my iPad using Tapatalk


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## augustinionut (May 30, 2016)

HKLM\HARDWARE\DESCRIPTION\System\CentralProcessor\0\.....Mhz.


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## zombiegator (May 30, 2016)

augustinionut said:


> HKLM\HARDWARE\DESCRIPTION\System\CentralProcessor\0\.....Mhz.

Click to collapse





Interesting note, I have 0,1,2,3,4,5 and each have a MHz value inside, could that be the different threads? I didn't think I had 6 of them, and now I'm afraid to change the values [emoji24]. Ps using a L950


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## w.bogdan (May 31, 2016)

augustinionut said:


> HKLM\HARDWARE\DESCRIPTION\System\CentralProcessor\0\.....Mhz.

Click to collapse



I think that is just a description, as the name suggests, it doesn't alter the functionality.


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## lukjok (May 31, 2016)

On Lumia 930 and I think other Lumias there is a power management driver.  You can find parameters here:
HKLM\System\ControlSet001\Services\QCPEP\Parameters\
And the most important keys are FrequencyCap and DisableFrequencyCap also DisableCPUBoost
But I can't edit these keys


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## w.bogdan (May 31, 2016)

lukjok said:


> HKLM\System\ControlSet001\Services\QCPEP\Parameters\

Click to collapse



I have something different


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## lukjok (May 31, 2016)

This is from my Lumia 930


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## GoranBL (May 31, 2016)

Contents of file "system32/drivers/ QCpep8612.sys" shows  possible keys for  qcpep\Parameters subkey.
I marked it as a code because keys show no space between them.



```
\ R e g i s t r y \ M a c h i n e \ S y s t e m \ C u r r e n t C o n t r o l S e t \ S e r v i c e s \ q c p e p \ P a r a m e t e r s     CPU DCVS    cc_apcs_c%d_clk \ R e g i s t r y \ M a c h i n e \ S y s t e m \ C u r r e n t C o n t r o l S e t \ S e r v i c e s \ q c p e p \ P o w e r S e t t i n g s   MMFAB Client    /clk/bus/mmfab  SMI Client  /clk/mem/smi    PepSelectPState PEP_PState_Mgmt.c   PepPerformanceWorkV2    PEP : Aggr_AddFsResource: NULL name
    PEP : Aggr_AddFsResource:  Name Length is 0
    PEP: PSTATE_ADJUST from a D-state is not supported on Multi-Component devices
  AdjustAResource PEP_ResourceMgmt.c  Driver: %s  PepStatus 0x%08x    TEMP_PEP_BUS    \ N U L L   D i s a b l e C X O     D i s a b l e C p u V d d   D i s a b l e C p u R e t   D i s a b l e L 2 C o l l a p s e   D i s a b l e L 2 G D H S   D i s a b l e V d d M i n   E n a b l e P r o c e s s o r M a n a g e m e n t   E n a b l e T h e r m a l M o n i t o r     E n a b l e V P P M         S k i p G r a p h i c s S e t L a t e n c y W o r k A r o u n d     D i s a b l e R p m H a l t     R e a d C P U P e r f C l o c k     P x o P o w e r C o l l a p s e L e d E n a b l e   S y s t e m L a t e n c y F l a g s     E n a b l e T h e r m a l D e b u g     S y s t e m D e f a u l t S t a t e     D i s a b l e C P R     D i s a b l e C o r e R o t a t i o n   E n a b l e P e p S t a t e T r a n s i t i o n E t w   E n a b l e P E P O C D T e s t     E n a b l e P E P O C D T e s t T o S D C a r d     R p m C p r S t a t s M i l l i s   B C L P o l l i n g P e r i o d     D i s a b l e P h a s e S c a l i n g   D i s a b l e O f f l i n e N o t i f i c a t i o n     E n a b l e T s e n s O f f s e t   D i s a b l e P E P Q D S S L o g s     T s e n s O f f s e t T e m p e r a t u r e     E n a b l e V a d c O f f s e t     W P P E n a b l e d     I d l e S t a t s A p p L o g g i n g E n a b l e   E n a b l e I d l e C r a s h D e b u g     E n a b l e N e g a t i v e O f f s e t     N e g a t i v e O f f s e t T e m p e r a t u r e   D i s a b l e S p m W a k e D e l a y       \ R e g i s t r y \ M a c h i n e \ S y s t e m \ C u r r e n t C o n t r o l S e t \ S e r v i c e s \ q c p e p \ D i a g n o s t i c s
```


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## augustinionut (May 31, 2016)

HKLM\SYSTEM\Setup\WOF\MaxMHz


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## zombiegator (Jun 1, 2016)

Does anyone have a test device that they could use to test these keys? I am not sure I want to go around and try changing things on my phone until I'm sure we know what these registry keys do


Sent from my iPad using Tapatalk


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## ngame (Jun 1, 2016)

lukjok said:


> On Lumia 930 and I think other Lumias there is a power management driver.  You can find parameters here:
> HKLM\System\ControlSet001\Services\QCPEP\Parameters\
> And the most important keys are FrequencyCap and DisableFrequencyCap also DisableCPUBoost
> But I can't edit these keys

Click to collapse



ِdo not try to change ControlSet001. try this one:
HKLM\System\ControlSet001\Services\QCPEP\Parameters\
My phone is a L950XL and I think it doesn't allow me to change System subkey values . but I think you can change it .
and also I have to say set Max and Current MHz values together , Or at least do not set MaxMhz less than Current .


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## lukjok (Jun 1, 2016)

ngame said:


> ِdo not try to change ControlSet001. try this one:
> HKLM\System\ControlSet001\Services\QCPEP\Parameters\
> My phone is a L950XL and I think it doesn't allow me to change System subkey values . but I think you can change it .
> and also I have to say set Max and Current MHz values together , Or at least do not set MaxMhz less than Current .

Click to collapse



First of all, I can't edit MaxMhz or CurrentMhz as also I can't edit keys in QCPEP. Secondly, I think these values can be edited only when phone is in Mass Storage mode or deploying packages via IUTool, but this requires Test mode enabled in BCD.


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## ngame (Jun 1, 2016)

lukjok said:


> First of all, I can't edit MaxMhz or CurrentMhz as also I can't edit keys in QCPEP. Secondly, I think these values can be edited only when phone is in Mass Storage mode or deploying packages via IUTool, but this requires Test mode enabled in BCD.

Click to collapse



Maybe you're right .not a beautiful way for Over Clock and under clock


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## fauntelroy (Jul 27, 2016)

lets say I has changed those key,

how can I know that it's actually worked?how do I find out the current speed?


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## adijagiel (Jul 27, 2016)

fauntelroy said:


> lets say I has changed those key,
> 
> how can I know that it's actually worked?how do I find out the current speed?

Click to collapse



Maybe via this tool?  http://forum.xda-developers.com/win...-device-diagnostics-hub-performances-t3276664


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## fauntelroy (Jul 27, 2016)

adijagiel said:


> Maybe via this tool?  http://forum.xda-developers.com/win...-device-diagnostics-hub-performances-t3276664

Click to collapse



nah I already tried that,it's only showed % of processor usage not the current speed.

any other suggestion??


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## lukjok (Jul 27, 2016)

fauntelroy said:


> nah I already tried that,it's only showed % of processor usage not the current speed.
> 
> any other suggestion??

Click to collapse



Try Aida64 from Store


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## fauntelroy (Jul 28, 2016)

lukjok said:


> Try Aida64 from Store

Click to collapse



tried that too,but it only show max processor speed

I changed registry for :
HKLM\System\ControlSet001\Services\QCPEP\Parameter
I changed both FrequencyCap and DisableFrequencyCap so to make it sure it really worked out I need to find out the current speed of processor,maybe something like cpu-z in desktop

I also tried antutu to see if there is any difference before and after I changed those value,the result was differ by around 5000(just the cpu test) but I don't really believe those number, I need something real to show the exact processor speed.


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## lukjok (Jul 28, 2016)

fauntelroy said:


> tried that too,but it only show max processor speed
> 
> I changed registry for :
> HKLM\System\ControlSet001\Services\QCPEP\Parameter
> ...

Click to collapse



So, I created a small app which shows each core frequency in real-time. 
Note: If an app won't work, deploy Microsoft.VCLibs.ARM.14.00.appx package.


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## fauntelroy (Jul 28, 2016)

lukjok said:


> So, I created a small app which shows each core frequency in real-time.
> Note: If an app won't work, deploy Microsoft.VCLibs.ARM.14.00.appx package.

Click to collapse



great this is what I need,
the result was attached below (FYI my normal speed was 2.5)

so if this app was correct then the answer of OP question is yes we can underclock in wm10
don't know about overclock though,i don't really interested in oc

thanks for the app luk


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## lukjok (Jul 28, 2016)

fauntelroy said:


> great this is what I need,
> the result was attached below (FYI my normal speed was 2.5)
> 
> so if this app was correct then the answer of OP question is yes we can underclock in wm10
> ...

Click to collapse



Nice to hear this! By the way, do you notice any UI responsiveness problems?


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## augustinionut (Jul 28, 2016)

Lumia 640 XL DS: min freq=300MHz, max. freq. = 1190MHz. All 4 core are acting equal.


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## fauntelroy (Jul 28, 2016)

lukjok said:


> Nice to hear this! By the way, do you notice any UI responsiveness problems?

Click to collapse



at those freq I noticed some lag or stutter,barely visible but I know it's there.
I used this setting all day today and the most noticeable difference was the phone doesn't heat up when browsing in edge

oh I attached my normal processor reading without the registry change,just to make sure it's really working


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## ngame (Jul 28, 2016)

lukjok said:


> So, I created a small app which shows each core frequency in real-time.
> Note: If an app won't work, deploy Microsoft.VCLibs.ARM.14.00.appx package.

Click to collapse



Sorry your app can detect only 4 cores or Lumia 950XL doesn't work with 8 CPU cores ?
Last I checked I can remember it had 8 Subkeys from 0 to 7 for each core .


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## spavlin (Jul 28, 2016)

Ativ S




But only:
[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\QCpep\Parameters]
"DisablePxoCxoSplit"=dword:1
"SystemLatencyFlags"=dword:0


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## Seyar.q (Jul 29, 2016)

spavlin said:


> Ativ S
> 
> 
> 
> ...

Click to collapse



Same keys here in Lumia 1020 with RS. No sign of FrequencyCap and DisableFrequencyCap.
What to change now?


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## fauntelroy (Jul 29, 2016)

looks like not every phone has those power management driver hence they missing those reg key.

my phone chip was msm8974 and I think lukjok has the same chip so we got those reg key,anybody can confirm this?

maybe we can find other registry value to change the frequencies,if anybody find other registry for processor frequencies I can test it


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## lukjok (Jul 29, 2016)

ngame said:


> Sorry your app can detect only 4 cores or Lumia 950XL doesn't work with 8 CPU cores ?
> Last I checked I can remember it had 8 Subkeys from 0 to 7 for each core .

Click to collapse



Yeah, currently it only supports up to 4 cores. I will update app shortly.



Seyar.q said:


> Same keys here in Lumia 1020 with RS. No sign of FrequencyCap and DisableFrequencyCap.
> What to change now?

Click to collapse



Your Lumia has Snapdragon S4 Plus SOC, so I think that this chip does not have some power management features.



fauntelroy said:


> looks like not every phone has those power management driver hence they missing those reg key.
> 
> my phone chip was msm8974 and I think lukjok has the same chip so we got those reg key,anybody can confirm this?
> 
> maybe we can find other registry value to change the frequencies,if anybody find other registry for processor frequencies I can test it

Click to collapse



Yes, you are right. My Lumia has Snapdragon 800 SOC, same as yours.


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## lukjok (Jul 29, 2016)

So, I updated an app, now it supports up to 8 cores (Snapdragon 810; Snapdragon 808). 
Download here:


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## pijalaccount (Jul 30, 2016)

*power management it work too*

after latest redstone update i cant change qcpep, but i can limit processor speed with power management from windows like pc used

there is 3 power scheme include Balance, High performance, and power saver. default set is balance and it always. we cant set to High performance or power saving because there is no UI to change that. but you can go inside registry to change them 
for Maximum processor state: (balance)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\bc5038f7-23e0-4960-96da-33abaf5935ec\DefaultPowerSchemeValues\381b4222-f694-41f0-9685-ff5bb260df2e

type DWORD
AcSettingIndex=100
DcSettingIndex=100 (recommanded 50 if you want battery longger)
available value 0-100 (in percentage)

there is many key under 54533251-82be-4824-96c1-47b60b740d00 for processor power policy include core parking too. try it and its work


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## LagSeeN (Jul 31, 2016)

pijalaccount said:


> after latest redstone update i cant change qcpep, but i can limit processor speed with power management from windows like pc used
> 
> there is 3 power scheme include Balance, High performance, and power saver. default set is balance and it always. we cant set to High performance or power saving because there is no UI to change that. but you can go inside registry to change them
> for Maximum processor state: (balance)
> ...

Click to collapse



Yes it work
I am set 70


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## Y2000 (Aug 1, 2016)

And overclock? Is possible to equal 640 to 650 1.3 GHz?


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## lukjok (Aug 1, 2016)

Y2000 said:


> And overclock? Is possible to equal 640 to 650 1.3 GHz?

Click to collapse



For now, I think this is not possible.


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## Y2000 (Aug 6, 2016)

So, changing the FrequencyCap key to a higher value can overclock? And adding this key on Snapdragon 400 devices works? 

(sorry for my bad english)


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## lukjok (Aug 6, 2016)

Y2000 said:


> So, changing the FrequencyCap key to a higher value can overclock? And adding this key on Snapdragon 400 devices works?
> 
> (sorry for my bad english)

Click to collapse



Nope, I think that "FrequencyCap" can only limit CPU frequency. If you want to overclock you must bump up a voltage a bit. Also, that key presence depends on SOC power engine plug-in (PEP) driver, if this key doesn't exist, there is a little chance that key will have some influence. Anyway, I need to look at PEP driver for Snapdragon 400.


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## Y2000 (Aug 8, 2016)

I've tested this key on Lumia 435, no effect at all. We need a way to overclock Snapdragon 400 Lumias XD


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## pijalaccount (Aug 10, 2016)

Y2000 said:


> I've tested this key on Lumia 435, no effect at all. We need a way to overclock Snapdragon 400 Lumias XD

Click to collapse



i recommend don't overclock your smartphone it can burn your hand 
if you want processor more responsive on sensitive tasks (open apps, scrolling webpages, touch response) try changing this key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\619b7505-003b-4e82-b7a6-4dd29c300971\DefaultPowerSchemeValues\381b4222-f694-41f0-9685-ff5bb260df2e

type DWORD
AcSettingIndex= 56 (recommended 99)
DcSettingIndex= 56 (recommended 99)


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## BlueTR (Aug 10, 2016)

Guys I found something else.

HKLM\HARDWARE\DESCRIPTION\System\CentralProcessor

You will see subkeys according to your processors cores. Since I have Lumia 630 with Snapdragon 400 I have 4 subkeys. 
Under these subkeys there is a value named "~MHz" I didn't change it because I wont be able to install W10 anymore if something happens.
Default value is 787 for Snapdragon 400 MSM8226.


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## bloover (Sep 13, 2017)

is there a guide for lumia 950XL?
a guide for interop unlock and then underclock, my phone is always hot and battery go away real quick....


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## RedGreenBlue123 (Jun 19, 2018)

lukjok said:


> First of all, I can't edit MaxMhz or CurrentMhz as also I can't edit keys in QCPEP. Secondly, I think these values can be edited only when phone is in Mass Storage mode or deploying packages via IUTool, but this requires Test mode enabled in BCD.

Click to collapse



But I can edit on my Lumia Icon
I overclocked it to 2365MHZ


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## augustinionut (Jun 19, 2018)

lukjok said:


> So, I created a small app which shows each core frequency in real-time. .

Click to collapse



Hello. Can you make the app to show 8 CPU cores? Lumia950XL


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## titi66200 (Jun 19, 2018)

@augustinionut 
Please read all post
https://forum.xda-developers.com/showpost.php?p=67952773&postcount=31


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## naryhd (Mar 28, 2019)

hi
can anyone help me? i want to underclock my old lumia 950, after a year i think i picked it up from my drawer , and start to update it , and downloading some apps, it gets too damn hot, it was nearly burning ? did factory reset but nothing changes, installed its rom with pc , again nothing changed, so i want to underclock its processor , so it will be cool in every situation , i think ?


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## naryhd (Mar 29, 2019)

pijalaccount said:


> i recommend don't overclock your smartphone it can burn your hand
> if you want processor more responsive on sensitive tasks (open apps, scrolling webpages, touch response) try changing this key
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\619b7505-003b-4e82-b7a6-4dd29c300971\DefaultPowerSchemeValues\381b4222-f694-41f0-9685-ff5bb260df2e
> 
> ...

Click to collapse



hi if i want to use only 50% of my cpu, what should i set these values???


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