# Undervolting my Y540



## Creedex (Nov 28, 2022)

Hey, I got a Legion Y540 ( i7-9750H , RTX 2060).

I undervolted my CPU using ThrottleStop from a youtube video I saw.

Now when Im gaming my CPU goes to 70C witch is great , but I feel that my PC fell abit from performance is that possible?

Any advice on my Settings?

Thanks


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## unclewebb (Nov 28, 2022)

Why are you still using ThrottleStop 8.70? That version is ancient. 

Download ThrottleStop 9.5. Open the TPL window and check the MMIO Lock box near the top right. Post some updated screenshots of the main window, the FIVR and TPL windows.

Your screenshot above shows you have lowered the PL1 and PL2 power limits to 24. That is what is killing performance. The 9750H has a 45W TDP rating. You are not going to get maximum performance if you limit the power to only 24W. If you want maximum performance, set both power limits to 60W. If your computer runs too hot, open it up and clean it out. Replace the thermal paste if blowing out the dust and dirt does not fix your problem. 

Stop following YouTube guides that recommend dumb stuff like reducing the power limits to 24W. 

Your screenshot above shows that your computer is throttling even when it is idle. Something is not right. Run a new log file that covers about 15 minutes of gaming.


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## Creedex (Nov 28, 2022)

unclewebb said:


> Why are you still using ThrottleStop 8.70? That version is ancient.
> 
> Download ThrottleStop 9.5. Open the TPL window and check the MMIO Lock box near the top right. Post some updated screenshots of the main window, the FIVR and TPL windows.
> 
> ...


Here are the new Main window, FIVR and TPL windows (checked the MMIO Lock box after the screenshots).
I changed the PL1 and PL2 to 60 as you said, My temp were going crazy when i was gaming.
I really didnt repaste my laptop ever and I got it for 2.5 years.
So listen I will tommorow repaste my laptop and see if my temps are ok, any way is these settings ok, anything i need to change?
Thanks again!


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## unclewebb (Nov 29, 2022)

If cleaning out your laptop improves your temperatures, you can think about increasing PL2 to 70W. If you see no improvement then consider reducing PL1 to 50W or 45W and reduce PL2 to maybe 55W or 50W. I think reducing the turbo time limit to less than the default 28 seconds is a good idea for most laptops. If your cooling cannot handle running your CPU at PL2 for 28 seconds then use a shorter time value. It all depends on your cooling. Perhaps 8 seconds at full power is more appropriate compared to 28 seconds. 

I set IccMax for both the core and the cache to the maximum, 255.75. I also set Power Limit 4 to a value of 0 which should disable this limit. 

In the Options window check the Windows Defender Boost box. 

Everything looks OK. Hopefully the paste job goes well. You are just on the edge of thermal throttling. It does not appear to be costing you too much performance at the moment. You can look forward to full performance if you can improve the temperatures a few degrees.


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## Creedex (Nov 29, 2022)

unclewebb said:


> If cleaning out your laptop improves your temperatures, you can think about increasing PL2 to 70W. If you see no improvement then consider reducing PL1 to 50W or 45W and reduce PL2 to maybe 55W or 50W. I think reducing the turbo time limit to less than the default 28 seconds is a good idea for most laptops. If your cooling cannot handle running your CPU at PL2 for 28 seconds then use a shorter time value. It all depends on your cooling. Perhaps 8 seconds at full power is more appropriate compared to 28 seconds.
> 
> I set IccMax for both the core and the cache to the maximum, 255.75. I also set Power Limit 4 to a value of 0 which should disable this limit.
> 
> ...


I cleaned my laptop and repasted and the temps got alot better.
I am attaching 2 logs, 1 is after repaste and before the new settings of gaming, the other is after repaste and with the new settings of gaming.
The settings I changed are:
*-PL2 to 70W
-IccMax 255.75 both core and cache
-Checked Windows Defender Boost box*
I didnt change the Turbo time limit and the Power Limit (Turbo time limit is 28, Power Limit 4 value is 160).
I did a TS bench and I get errors (once I got 8 errors and once 20 errors).
So from these logs and bench should I change the Turbo time limit or the Power Limit?
Thanks alot again!


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## unclewebb (Nov 29, 2022)

Creedex said:


> I did a TS bench and I get errors


It is rare to see a 9750H that is 100% stable when the cache undervolt is set to -140 mV. You should not see any errors when running the TS Bench. If it was my computer, I would reduce the cache offset to -125 mV and then test again for errors.

Some people choose to ignore a few TS Bench errors. One guy told me that he wished he had listened to what ThrottleStop was telling him. A month later Windows went down hard and he lost a lot of his work. Do not be surprised if a few random errors slowly corrupt Windows over a period of time. Your temperatures are much better so there is no reason to use an undervolt that is right on the very edge of stability. Of course, -140 mV is taking you over that edge. 

Other than that, everything looks great. The Legion Y540 series have better cooling compared to many similar laptops with 9750H CPUs. As long as the thermal paste does not pump out, your laptop should be good for a while.


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## Creedex (Nov 29, 2022)

unclewebb said:


> It is rare to see a 9750H that is 100% stable when the cache undervolt is set to -140 mV. You should not see any errors when running the TS Bench. If it was my computer, I would reduce the cache offset to -125 mV and then test again for errors.
> 
> Some people choose to ignore a few TS Bench errors. One guy told me that he wished he had listened to what ThrottleStop was telling him. A month later Windows went down hard and he lost a lot of his work. Do not be surprised if a few random errors slowly corrupt Windows over a period of time. Your temperatures are much better so there is no reason to use an undervolt that is right on the very edge of stability. Of course, -140 mV is taking you over that edge.
> 
> Other than that, everything looks great. The Legion Y540 series have better cooling compared to many similar laptops with 9750H CPUs. As long as the thermal paste does not pump out, your laptop should be good for a while.


So I reduced the cache offset to -125 and the core offset is till -140 and I get no errors.
Should I still change the Turbo time limit or the Power Limit?(Currently Turbo time limit is 28, Power Limit 4 value is 160)
Thanks alot for your help


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## unclewebb (Nov 29, 2022)

You do not have any thermal or throttling issues so leave everything as is if you are happy how your laptop is running. Fixing the cooling problem made a big difference. You could bump the power limits up some more. I think PL1=70W and PL2=90W were popular settings for well cooled laptops with a 9750H. It is OK to leave the turbo time limit set to 28 seconds as long as there are no issues. 

I always set Power Limit 4 to 0. It seems to be an unnecessary power limit. You can leave it at 160 if it is not causing you any problems.


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## Creedex (Nov 29, 2022)

unclewebb said:


> You do not have any thermal or throttling issues so leave everything as is if you are happy how your laptop is running. Fixing the cooling problem made a big difference. You could bump the power limits up some more. I think PL1=70W and PL2=90W were popular settings for well cooled laptops with a 9750H. It is OK to leave the turbo time limit set to 28 seconds as long as there are no issues.
> 
> I always set Power Limit 4 to 0. It seems to be an unnecessary power limit. You can leave it at 160 if it is not causing you any problems.


When I run TS bench the "POWER" in red pops up, is that OK?


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## unclewebb (Nov 29, 2022)

If you want less power limit throttling, increase the power limits some more. Open up Limit Reasons to see which power limit is causing the problem. Your temps are OK so increase PL1 to 75W or 80W. The amount of throttling in your screenshot is very minor.

Edit - I just had a second look. Lenovo likes to set the throttling temperature on the low side. Open the Options window and see if the PROCHOT Offset setting has a lock icon near it. If this setting is not locked you could lower the offset value to raise the throttling temperature a few degrees.

At the end of the day it is a laptop. Instead of full load bench tests, go play some games. How is gaming performance now? It should be wonderful compared to how your computer was running when it was set to 24W.


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## Creedex (Nov 29, 2022)

unclewebb said:


> If you want less power limit throttling, increase the power limits some more. Open up Limit Reasons to see which power limit is causing the problem. Your temps are OK so increase PL1 to 75W or 80W. The amount of throttling in your screenshot is very minor.
> 
> Edit - I just had a second look. Lenovo likes to set the throttling temperature on the low side. Open the Options window and see if the PROCHOT Offset setting has a lock icon near it. If this setting is not locked you could lower the offset value to raise the throttling temperature a few degrees.
> 
> At the end of the day it is a laptop. Instead of full load bench tests, go play some games. How is gaming performance now? It should be wonderful compared to how your computer was running when it was set to 24W.


I set the PL1 to 75 and PL2 to 90 and now I dont have the POWER popping up.
Dont have a lock on the PROCHOT Offset (Attaching a settings picture).
Did not touch the offsets, currently Cache -125 and Core -140.
Is these settings OK now?


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## unclewebb (Nov 29, 2022)

PROCHOT Offset is set to 6 in the Options window. That tells your CPU to start thermal throttling at 94°C instead of the Intel recommended 100°C. Leave it as is if you think throttling at 94°C is OK. Reduce the offset if you want your CPU to be able to run at higher temperatures. You will not hurt your CPU no matter what you set this to. Not sure why manufacturers set this so conservatively. 

Do some Cinebench testing. Some users get slightly better results or better temperatures when the core is closer to  -175 mV. If you change this, run the TS Bench again to make sure you are still error free. 



Creedex said:


> Is these settings OK now?


Your settings are fine. Any performance improvements?


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## Creedex (Nov 29, 2022)

unclewebb said:


> PROCHOT Offset is set to 6 in the Options window. That tells your CPU to start thermal throttling at 94°C instead of the Intel recommended 100°C. Leave it as is if you think throttling at 94°C is OK. Reduce the offset if you want your CPU to be able to run at higher temperatures. You will not hurt your CPU no matter what you set this to. Not sure why manufacturers set this so conservatively.
> 
> Do some Cinebench testing. Some users get slightly better results or better temperatures when the core is closer to  -175 mV. If you change this, run the TS Bench again to make sure you are still error free.
> 
> ...


Ok so I changed the Core offset to -175 and Cache offset to -130 and no errors I will keep it that way, also put Power Limit 4 to 0.
I think these settings are final and good.
I feel that the performance is alot better from the start thanks to you!


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## Creedex (Dec 1, 2022)

unclewebb said:


> PROCHOT Offset is set to 6 in the Options window. That tells your CPU to start thermal throttling at 94°C instead of the Intel recommended 100°C. Leave it as is if you think throttling at 94°C is OK. Reduce the offset if you want your CPU to be able to run at higher temperatures. You will not hurt your CPU no matter what you set this to. Not sure why manufacturers set this so conservatively.
> 
> Do some Cinebench testing. Some users get slightly better results or better temperatures when the core is closer to  -175 mV. If you change this, run the TS Bench again to make sure you are still error free.
> 
> ...


Hey I noticed that my GPU clock is lower than it should be, do you know why?


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## unclewebb (Dec 1, 2022)

Your screenshot shows GPU power is at 79W. Does your laptop have an 80W GPU power limit? It probably does. The Nvidia GPU will have to throttle so it does not exceed 80W. That is probably what the problem is.

Run GPU-Z. It should be able to show you if your Nvidia GPU is power limit throttling.


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## Creedex (Dec 1, 2022)

unclewebb said:


> Your screenshot shows GPU power is at 79W. Does your laptop have an 80W GPU power limit? It probably does. The Nvidia GPU will have to throttle so it does not exceed 80W. That is probably what the problem is.
> 
> Run GPU-Z. It should be able to show you if your Nvidia GPU is power limit throttling.


I run it while gaming, I hope I took the right screenshot.


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## unclewebb (Dec 1, 2022)

For Performance Cap Reason near the bottom it shows Pwr. In other words, constant power limit throttling of the Nvidia GPU. Kind of what I thought. Maybe there is a moded BIOS available for your GPU which has an increased power limit. Probably best to just leave it as is. At least the CPU is running decent.


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## Taraquin (Dec 2, 2022)

If you undervolt GPU aswell CPU may perform a bit better since they share cooling solution. Flat line in Afterburner at 1470-1560 depending on binning and a slight OC on vram gives you about 90-95% of performance at typically lower noise, 5-10C lower temp and better CPU temps/performance.


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## Creedex (Dec 2, 2022)

unclewebb said:


> For Performance Cap Reason near the bottom it shows Pwr. In other words, constant power limit throttling of the Nvidia GPU. Kind of what I thought. Maybe there is a moded BIOS available for your GPU which has an increased power limit. Probably best to just leave it as is. At least the CPU is running decent.


I understand, I ran a AIDA64 CPU bench test, and it shows that the cpu is throttling, cpu temps get to 97-96.
Is that OK?


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## unclewebb (Dec 2, 2022)

Creedex said:


> Is that OK?


Throttling is never OK. 

When you run a full load stress test on a laptop, you should not be too surprised if the CPU gets hot. Most 9750H laptops either power limit throttle or thermal throttle depending on your settings. I am not sure which one is worse or if it makes any difference. Throttling slows down your CPU. You might need to buy a water cooled desktop computer if running full load stress tests is important to you.


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## Creedex (Dec 2, 2022)

unclewebb said:


> Throttling is never OK.
> 
> When you run a full load stress test on a laptop, you should not be too surprised if the CPU gets hot. Most 9750H laptops either power limit throttle or thermal throttle depending on your settings. I am not sure which one is worse or if it makes any difference. Throttling slows down your CPU. You might need to buy a water cooled desktop computer if running full load stress tests is important to you.


Ok I understand you thanks.

Edit: At the Logs when I game the temps arent stable is it a mean between all the cores?
2022-12-03  01:32:40  40.13   40.3  100.0       0   70   1.1189   38.5
2022-12-03  01:32:41  40.47   23.9  100.0       0   78   1.0472   23.2
2022-12-03  01:32:42  40.29   24.9  100.0       0   81   1.0641   28.8
2022-12-03  01:32:43  39.96   70.7  100.0       0   93   1.0581   44.4
2022-12-03  01:32:44  40.03   32.8  100.0       0   82   1.0756   36.2
2022-12-03  01:32:45  40.01   29.6  100.0       0   81   1.0693   30.2
2022-12-03  01:32:46  40.00   43.0  100.0       0   73   1.0486   39.5
2022-12-03  01:32:47  40.12   24.9  100.0       0   74   1.0923   21.2
2022-12-03  01:32:48  40.88   17.0  100.0       0   62   1.0972   16.8


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## unclewebb (Dec 3, 2022)

The log records the CPU package temperature which is usually the peak core temperature when you are actually using your computer. The far right column shows power consumption which appears to be varying significantly every second. Real world apps like games do not always provide a steady CPU load like a stress test does. If power consumption is varying significantly, your peak CPU temperature will also be varying. The heatsinks in laptops are tiny and inadequate. 

Stop worrying about the details. If your games play smoothly, there is nothing to worry about. Intel says anything under 100°C is a safe operating temperature. Their CPUs do a great job of looking after themselves so users do not need to worry.


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