# How to undervolt my CPU (i7-8750H)



## CLutch_ (Jan 22, 2022)

So I've looked through a few threads about it but I'm still struggling to get my CPU to stay under 95 degrees in Cinebench, during gaming my CPU is fine (currently running a -180.7mV undervolt on CPU Core and CPU Cache, CPU mostly stays under 80 degrees if it's like 30 degrees outside), could anyone possibly help me to try and control my temps? Thanks in advance










I also get EDP Other Limits under Ring after a gaming session


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## unclewebb (Jan 25, 2022)

CLutch_ said:


> currently running a -180.7mV undervolt on CPU Core and CPU Cache


I have never seen an 8750H that was 100% stable at an undervolt of -180 mV. Do you get any errors during a TS Bench test? If you see any errors, I would reduce the cache offset. If you see any errors, it is not a good idea to ignore them. Long term, you could end up corrupting Windows or some other important files on your computer.



CLutch_ said:


> CPU mostly stays under 80 degrees


Your temperatures are normal for a 6 core CPU shoved into a laptop. If you need to spend all day fully loading your CPU with programs like Cinebench, consider buying a desktop computer. They have much better cooling options. Your laptop gaming temps are perfect. 

When you undervolt the Intel GPU, it is the iGPU Unslice that must be set to the same offset voltage value as the Intel GPU. The System Agent and Intel GPU do not need to be set to the same value. Your probably have a Nvidia GPU for gaming so undervolting the Intel GPU is not necessary. It can cause instability without reducing power or temperatures any meaningful amount.


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## CLutch_ (Jan 25, 2022)

unclewebb said:


> I have never seen an 8750H that was 100% stable at an undervolt of -180 mV. Do you get any errors during a TS Bench test? If you see any errors, I would reduce the cache offset. If you see any errors, it is not a good idea to ignore them. Long term, you could end up corrupting Windows or some other important files on your computer.
> 
> 
> Your temperatures are normal for a 6 core CPU shoved into a laptop. If you need to spend all day fully loading your CPU with programs like Cinebench, consider buying a desktop computer. They have much better cooling options. Your laptop gaming temps are perfect.
> ...


Thanks for the reply uncle, I've updated a few settings from then, my PC has been running stably at 170 but that's the only way it'll be 100% stable, and no I didn't get any errors in the TS bench, below you'll find my current settings and the results of the TS bench, also I removed the undervolt on my iGPU since I read in another post where you replied that it doesn't gain me any performance or lower my heat, like you just said.

Also on a hot day my CPU can get up to like 85 degrees (for at least more than a second) so that worries me a bit, my GPU is fine though, even at 100% usage it reaches a max of 73 degrees, but my CPU at 100% gets scarily hot, I don't run tests long enough to get a result (as you can see my results after the TS bench

Edit: Lol nevermind, my PC just froze up, turned it down to -160mV


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## unclewebb (Jan 25, 2022)

CLutch_ said:


> scarily hot


No need to be scared. Intel has been using the same 100°C thermal throttling temperature for almost every Core i CPU that they have produced going back over 13 years. For a few years they were even setting the thermal throttling temperature to 105°C. If peak core temperatures up over 90°C were causing any reliability problems, Intel would have lowered this temperature specification many years ago.

Your laptop manufacturer has set PROCHOT Offset to 5. This lowers the thermal throttling temperature from the 100°C Intel default down to 95°C so your CPU will be extra safe. There is no reason to worry about your CPU temperature. Intel CPUs do a fantastic job of looking after themselves. They will automatically slow down as much as necessary to prevent against any damage. Hardware thermal throttling can adjust the CPU speed and temperature hundreds of times per second. No worries. 

It is great if your computer can run stable with the cache at -170 mV. Many 8750H start losing stability when the cache offset voltage is set to a number higher than -125 mV. All CPUs are unique. Looks like Intel set the default voltage curve too high for your CPU. Using ThrottleStop to undervolt fixes that problem. 

If you ever want to try and improve your temperatures, pull your laptop apart and try replacing the thermal paste. If your laptop runs fine as is, I would not bother doing this. You only need to replace the thermal paste if you are constantly seeing 100°C temperatures. Turn on the Log File option and play a game for a while. When done testing, check to see if there are any TEMP (temperature) warning messages in the far right column of the log file. Some random TEMP warning messages are OK. Constant TEMP messages would encourage me to replace the thermal paste.


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## CLutch_ (Jan 25, 2022)

unclewebb said:


> No need to be scared. Intel has been using the same 100°C thermal throttling temperature for almost every Core i CPU that they have produced going back over 13 years. For a few years they were even setting the thermal throttling temperature to 105°C. If peak core temperatures up over 90°C were causing any reliability problems, Intel would have lowered this temperature specification many years ago.
> 
> Your laptop manufacturer has set PROCHOT Offset to 5. This lowers the thermal throttling temperature from the 100°C Intel default down to 95°C so your CPU will be extra safe. There is no reason to worry about your CPU temperature. Intel CPUs do a fantastic job of looking after themselves. They will automatically slow down as much as necessary to prevent against any damage. Hardware thermal throttling can adjust the CPU speed and temperature hundreds of times per second. No worries.
> 
> ...


So should I try to undervolt my Core or Cache more and then check for stability? I've seen in other posts that you said people can run the cache and core at different offsets. Also I just replaced the thermal paste a few weeks ago (thermal grizzly) so that brought my temperatures down by about 10 degrees, and I'll turn on the Log File and when I play some games I'll attach it here.

Also do you suggest I change any other settings in the main/FIVR/TPL windows?


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## unclewebb (Jan 25, 2022)

CLutch_ said:


> do you suggest I change any other settings


You can try changing whatever you want but I think you are close to as good as it is going to get. There is very little room for any improvements. Post a log file so I can see how your laptop performs while gaming.


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## CLutch_ (Jan 26, 2022)

Turned on Log File before I started the game, temprature outside is ~27 degrees C

Also I found this video 







 that says you can turn off turbo boost and you won't lose much fps for a performance gain, I assume this is for if your CPU is at like 90+ degrees while gaming but I just wanted to get your opinion on if I should do it, after looking at the Log File

Just played some more, 28 degrees outside, here are the results after just 10 minutes of playing (I started logging after I saw my temps getting to 90 degrees)


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## unclewebb (Jan 26, 2022)

CLutch_ said:


> you can turn off turbo boost and you won't lose much fps


When you disable turbo boost, an 8750H will be limited to 2.2 GHz. I would not recommend doing that. If you want cooler temperatures, lower the Turbo Ratio Limits in the FIVR window. This lets you control how much turbo boost your CPU uses. No need to completely disable turbo boost.

90°C for a modern gaming laptop is a normal operating temperature. You can slow your CPU down as much as you like but there is no need to do this.


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## CLutch_ (Jan 26, 2022)

Alright well thanks for your help then I really appreciate it, hopefully I'll be able to build a desktop soon (if/when the GPU crisis ends) and then I can have my 7 fan PC running cool

Also thanks for making throttlestop and responding to people's questions


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## Deleted member 74752 (Jan 26, 2022)

Build a 5600G or 5700G system and add a video card down the road...you won't be disappointed.


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## CLutch_ (Jan 26, 2022)

rickss69 said:


> Build a 5600G or 5700G system and add a video card down the road...you won't be disappointed.


Yeah I can't afford that either, I need to pay for everything on credit, which in South Africa is a rarity, there's only 2 places here that allow you to pay for a prebuilt on credit, one's aftersales service is shocking and they're expensive, and the other one is just expensive


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## Gnetic (Jul 17, 2022)

unclewebb said:


> I have never seen an 8750H that was 100% stable at an undervolt of -180 mV. Do you get any errors during a TS Bench test? If you see any errors, I would reduce the cache offset. If you see any errors, it is not a good idea to ignore them. Long term, you could end up corrupting Windows or some other important files on your computer.
> 
> 
> Your temperatures are normal for a 6 core CPU shoved into a laptop. If you need to spend all day fully loading your CPU with programs like Cinebench, consider buying a desktop computer. They have much better cooling options. Your laptop gaming temps are perfect.
> ...


I think something is wrong with my undervolt, before it crashed at -150 and now even at -250 it doesn't crash


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## unclewebb (Jul 17, 2022)

Gnetic said:


> now even at -250 it doesn't crash


You can probably go to -1000 mV and it will not crash. This is only a request and the majority of this request will be ignored by the CPU. The core undervolt depends on the cache undervolt. You might see a small difference in some tests like Cinebench R23 when setting the core request about 100 mv more than the cache. When you go beyond this difference, there will be zero change in your temperatures and zero change in performance.

This means an offset of -125 mV cache and -225 mV for the core will likely give the exact same results as requesting -125 mV cache and -250 mV core or -500 mV for the core. Set the cache to -250 mV and you will definitely not be able to set the core at the same -250 mV. These two voltages are linked. Setting different values seems to only improve things when the CPU is running lots of AVX instructions. That is why Cinebench R23 is a great test when using different voltages.

I recommend that you enable Speed Shift Technology in the TPL window. Check the MMIO Lock box and upgrade to ThrottleStop 9.5.

If you have to lower the turbo ratios to 34 then you should think about cleaning out your laptop and replacing the thermal paste. You are losing a lot of performance because of poor cooling.


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## Ghostlu (Sunday at 12:53 AM)

@unclewebb can I ask you what changes between the Speed Shift EPP of the main tab and the Speed Shift (min and max values) in Miscellaneous of the TPL tab? Thank you in advance!


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## unclewebb (Sunday at 2:03 AM)

Speed Shift Min and Max in the TPL window can be used to control the minimum and maximum CPU speed.

Speed Shift EPP stands for Energy Performance Preference. Adjusting this allows software or the operating system to give the CPU some hints of what it would prefer; performance or energy savings. Setting EPP to 0 tells the CPU that you would prefer the CPU to run at maximum speed all of the time even when lightly loaded. Setting EPP to 84 is a good compromise for laptops because it allows the CPU to slow down when it is lightly loaded.

If you have a recent computer running Windows 10 or Windows 11, there is hardly ever a need to check the Speed Shift EPP box on the main screen of ThrottleStop. The Windows power plan will automatically set the EPP variable for you. The traditional Windows High Performance power plan sets EPP to 0 for maximum speed, all of the time, and the Balanced power plan usually sets EPP to 84. The FIVR monitoring table will show you the Speed Shift EPP value that the CPU is presently using. This may not work 100% correctly if you are using Windows 11 or if you have a 12th or 13th Gen CPU. I do not have access to any recent hardware or Windows 11 for testing purposes. Some users have reported that Speed Shift has changed on newer computers.

For any CPU, the EPP value is just a hint. Newer CPUs have the option to ignore this hint so they can adjust their speed however they like. I am not sure how common this feature is yet.


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## Ghostlu (Sunday at 2:26 AM)

unclewebb said:


> Speed Shift Min and Max in the TPL window can be used to control the minimum and maximum CPU speed.


You mean in GHz? I don't understand how to set the correct values (i7 8750H) and what they mean, min and max!


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## unclewebb (Sunday at 2:51 AM)

It shows you the suggested Min and Max values in the TPL window. No need to think so hard about this. For an 8750H, 8 is Min and 41 is Max. That will be the maximum multiplier. 

Try the suggested values. Try some random values and watch what happens to the CPU speed. Load the CPU with something simple like a TS Bench 1 Thread test. You can make changes while this test is running. Run a 960M test so it lasts for a while. You can stop the benchmark test at any time.

Do not be afraid to experiment. Doing is the best way to learn.


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## Ghostlu (Sunday at 3:08 AM)

unclewebb said:


> It shows you the suggested Min and Max values in the TPL window. No need to think so hard about this. For an 8750H, 8 is Min and 41 is Max. That will be the maximum multiplier.
> 
> Try the suggested values. Try some random values and watch what happens to the CPU speed. Load the CPU with something simple like a TS Bench 1 Thread test. You can make changes while this test is running. Run a 960M test so it lasts for a while. You can stop the benchmark test at any time.
> 
> Do not be afraid to experiment. Doing is the best way to learn.


You say that those are the min and max multipliers, but settings about ratios are on FIVR tab. For example, I did set 34 all cores on FIVR, but I see 41 as max in TPL Miscellaneous: should I put max 34 there too? I don't understand the meaning of those TPL settings


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## unclewebb (Sunday at 5:19 AM)

Try doing the testing I suggested so you can get a better understanding of how the turbo ratios and the Speed Shift Min and Max values change the CPU speed.

If you have any questions, post some screenshots of your tests.

The turbo ratios in the FIVR window are one way to control the CPU speed and the Speed Shift Min and Max values are a separate way to control the CPU speed. You do not have to use both control methods. Many computers have locked out the turbo ratio adjusters in the FIVR window. Changing the Speed Shift Min and Max values is a secondary control method that can be used to control the CPU speed even if the FIVR turbo ratio adjusters are locked.

If you think having two separate ways to control the CPU speed is redundant or stupid or not necessary then I mostly agree. Intel hired too many engineers that all seemed to be working on different throttling projects all at the same time. It seems like some of these projects happened without the engineers ever talking about what they were working on.

Here is a test. Set the turbo ratios to their default values and set Speed Shift Max to 30. Run a TS Bench 1 Thread test. What multiplier does ThrottleStop report while the CPU is loaded running this test?

Now do another test. Set Speed Shift Max to the recommended value of 41. When the the turbo ratios are lowered to 30, what multiplier does the CPU use?

Keep dreaming up new tests like this until you understand exactly how these two different control methods can be used to control the CPU. Run an infinite TS Bench 1 Thread test so you have an infinite amount of time to make adjustments while this test is running. This is the best way to learn what each setting does.

One thing you might learn is that the turbo ratios can only be used to reduce the CPU down to the base frequency. The 8750H has a base frequency of 2.20 GHz. If you want to force your 8750H to run slower than the base frequency, you can lower the Speed Shift Max value to accomplish this.

Try setting Speed Shift Min and Speed Shift Max to 8. What CPU speed do you get? I will give you a hint.
When Speed Shift Max is set to 8, does changing the turbo ratios in the FIVR window make any difference?


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## Ghostlu (Sunday at 4:39 PM)

So, it looks that if the TPL>Miscellaneous>Speed Shift is enabled, those values are more important that FIVR>Turbo Ratio Limits.
I think I should just disable the first one in TPL (removing the tick near "Speed Shift" in TPL), so I can control the exact ratio for each core just from FIVR.

What do you think?


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## unclewebb (Sunday at 5:50 PM)

If you can make your CPU run at the speed you want it to run at by adjusting only the FIVR turbo ratios then use that method. 

There is no right or wrong way to control a CPU. Use whatever method that works best for you. 



Ghostlu said:


> so I can control the exact ratio for each core


This is not possible. The FIVR settings only allow you to control the maximum multiplier based on how many cores are active at any moment in time. These Intel CPUs do not allow you to set different speeds for individual cores. You cannot set the first core to run at 40X while the second core is running at 36X. 

If you set the turbo ratios to 40, 37, 34, 31, 28, 25; anytime that 1 core is active, that active core will use the 40 multiplier. Any of your 6 cores will run at this speed as long as they are the only active core. If any two cores are active, the multiplier for both cores will be limited to 37. All active cores at any moment in time will always be using the same multiplier.  

Being able to control the maximum speed of each individual core would be a useful feature but it is not possible because of how Intel designed these CPUs.


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## Ghostlu (Sunday at 5:56 PM)

unclewebb said:


> If you can make your CPU run at the speed you want it to run at by adjusting only the FIVR turbo ratios then use that method.
> 
> There is no right or wrong way to control a CPU. Use whatever method that works best for you.
> 
> ...


Yeah sorry I didn't mean to control each individual core in a separate way, the FIVR settings are of course for the number of active cores at that moment. That's exactly what I meant.
Would you use the TPL>Miscellaneous>Speed Shift setting instead of FIVR to control ratios? What would you do for this i7 8750H? What about PL1 and PL2?


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## unclewebb (Sunday at 6:39 PM)

Ghostlu said:


> Would you use


I would use the turbo ratios in the FIVR window. These can be set to different values for each profile. This would allow you to set up a couple of different profiles so you can change the CPU speed depending on what game you are playing or whatever you are doing. 



Ghostlu said:


> What would you do for this i7 8750H?


What is your goal? I have never owned a laptop with an 8750H. Set PL1 and PL2 to at least 60W if your laptop cooling can handle that without the CPU overheating. 

Stop living in fear. Make some adjustments, do some testing and see if you like the results. You are the boss of your laptop. You are not going to hurt it.


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## Ghostlu (Sunday at 8:20 PM)

unclewebb said:


> I would use the turbo ratios in the FIVR window.


So, if I want to do the same, can I disable the tick on TPL>Miscellaneous>Speed Shift? I should not need that, since I want to control cores' behaviour from FIVR, right?

@unclewebb


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