# Cpu core undervolting not working



## joao0111 (Mar 8, 2022)

I have an Acer Nitro 5(i5-9300H) and yesterday I copied the final configuration that LemonScent6 achieved with unclewebb help (https://www.techpowerup.com/forums/threads/throttlestop-pl-2-yellow-on-core.264977/page-2) . it worked wonderfully for hours, dropped temp from 93ºC+ to 75ºC. Today I boot up my laptop and opening throttlesop don't seems to change the cpu core voltage. HWmonitor and the monitor from xtu says there's no change in the cpu core voltage but throttlesop says there's a -150mv offset. Here's screenshots from now and before, you can clearly see a drop on core voltage that don't exist anymore.
Any help would be greatly appreciated.

edit: cpu under load screenshot added, when I open throttlestop the core voltage drops suddenly.


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## unclewebb (Mar 8, 2022)

joao0111 said:


> don't seems to change the cpu core voltage.






ThrottleStop confirms that your CPU voltage is working correctly. Intel XTU does not always work correctly when other programs are changing the voltage. You can use Intel XTU or ThrottleStop but do not use them both at the same time. If you want to use both of them, you can trust the voltage data that ThrottleStop shows in the monitoring table. This data is accurately read every second from the CPU.

The Intel GPU and the iGPU Unslice need to be set equally or this will not work. I recommend only adjusting the CPU Core and the CPU Cache voltages. There is no reason to set the System Agent voltage equal to the Intel GPU voltage.



joao0111 said:


> HWmonitor and the monitor from xtu says there's no change in the cpu core voltage






The picture you posted shows HWMonitor is reporting your offset voltages. What HWMonitor reports is slightly different than what ThrottleStop reports. That is because ThrottleStop reports the offset voltages correctly, HWMonitor does not. HWMonitor is close though. It's calculation is off by 2% because it is using the wrong conversion factor.

When the CPU offset voltage register has a value of 1580.

HWMonitor = 1580 / 1000 = -0.1580 V = Wrong answer
ThrottleStop = 1580 / 1024 = -0.1543 V = Correct

ThrottleStop has to be running so it can apply the offset voltage. It does not make any changes to your CPU unless it is actually running. Is that what you are showing me? If you exit ThrottleStop and reboot or do a sleep resume cycle, all of your voltages will be reset to their default values. ThrottleStop does not write anything to the bios and it does not have a pile of background processes like XTU has constantly running. Do yourself a favor and uninstall XTU.


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## joao0111 (Mar 8, 2022)

Thanks for the reply. I was using both Throttlestop and XTU because of the graphs from XTU, following you advice I uninstalled it.

Intel GPU and the iGPU had different voltage offsets. I have now unchecked 'unlock Adjustable Voltage' on Intel GPU , on iGPUand and on System Agent.
Doing some testing with cinebench r20 showed me that when Turbo ratio Limits is lower (35 instead of 40) the max temp drops 10ºC. It's the same settings as the other user I mentioned, I don't know why the results are different.

Also, comparing the low Turbo Ratio Limit to yesterday it has 400 more points on cinebench r20 but has 7 more degrees.
Are those values good enough?

Again, thank you so much for sharing your knowledge.


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## unclewebb (Mar 9, 2022)

joao0111 said:


> I have now unchecked 'unlock Adjustable Voltage'


Before you uncheck this box you have to reset the offset voltage to zero. Set this to 0.0 and press Apply. You should see the offset voltage in the monitoring table return to +0.0000. Your screenshot shows that your previous offset voltages for the Intel GPU and the System Agent are still being applied. If you have already restarted your computer or did a sleep resume cycle, the offset voltages that you are no longer using have probably already been reset to zero. Check the FIVR monitoring table to make sure. 

Check the Speed Shift box in the TPL window so the Speed Shift Min and Max values get sent to the CPU.

One of your screenshots shows the CPU running at the 35.00 multiplier exactly. Do you remember if you changed anything to limit your CPU to this speed?

The 9300H has a 45W TDP rating so some PL1 power limit throttling right at 45.0W makes sense. Unfortunately this third power limit is enforced by the EC. Changing the MSR and MMIO power limits in ThrottleStop cannot be used to bypass the 45W limit that the manufacturer has set for your computer. Some computers have fully unlocked power limits. Your computer is locked to 45W.


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## joao0111 (Mar 9, 2022)

Thanks for the reply.


unclewebb said:


> Before you uncheck this box you have to reset the offset voltage to zero. Set this to 0.0 and press Apply. You should see the offset voltage in the monitoring table return to +0.0000. Your screenshot shows that your previous offset voltages for the Intel GPU and the System Agent are still being applied. If you have already restarted your computer or did a sleep resume cycle, the offset voltages that you are no longer using have probably already been reset to zero. Check the FIVR monitoring table to make sure.


I changed to 0.0 and now it shows +0.0000.







unclewebb said:


> Check the Speed Shift box in the TPL window so the Speed Shift Min and Max values get sent to the CPU.


Done.


unclewebb said:


> One of your screenshots shows the CPU running at the 35.00 multiplier exactly. Do you remember if you changed anything to limit your CPU to this speed?


Yes, in the 6th and 7th screenshots I was showing that the temperature is much lower when 'Turbo Ratio Limits' is set to 35, instead of 40. It's ok to do it?
The user with the same laptop as me in the other thread got 75ºC max with all values set to 40, but I can achieve that only when I set all Turbo Ratio Limits values to 35 (While losing 200 points on cinebench r20, compared to the other user). When all values are set to 40 I get 85ºC max.





unclewebb said:


> The 9300H has a 45W TDP rating so some PL1 power limit throttling right at 45.0W makes sense. Unfortunately this third power limit is enforced by the EC. Changing the MSR and MMIO power limits in ThrottleStop cannot be used to bypass the 45W limit that the manufacturer has set for your computer. Some computers have fully unlocked power limits. Your computer is locked to 45W.


Thanks for explaining that and all the other things.


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## unclewebb (Mar 10, 2022)

joao0111 said:


> when 'Turbo Ratio Limits' is set to 35, instead of 40. It's ok to do it?


Yes it is OK to do this. You can use ThrottleStop to run your CPU at any speed you want. You will not hurt it. A slow CPU should last forever.


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## joao0111 (Mar 10, 2022)

Great to know that my CPU will last longer, I stumbled across undervolting because I was concerned about the impact high temperatures could have on my laptop on the long term.
Today while gaming and testing I could see a big difference from what was happening, the max temperature was 65º, but only for a while, after that I could see it reach temperatures as high as 85ºC. In Cinebench r20 the temperatures reached 75ºC, but before I (probably) did a major mistake the max temperature on r20 was 65ºC. Can you take a look at my settings and tell me what can be done to improve that?
Thanks again.


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## unclewebb (Mar 10, 2022)

joao0111 said:


> CPU will last longer


A cool running CPU might last 50 years instead of only 40. Either way, it will likely be obsolete long before it dies from heat exhaustion. 



joao0111 said:


> as high as 85ºC


That is a normal operating temperature for an Intel mobile CPU. That is nothing to worry about. 

Intel sets the default thermal throttling temperature to 100°C. Your laptop BIOS has set a PROCHOT Offset value of 8. That means your laptop will thermal throttle at 92°C instead of the full 100°C. In other words, your laptop is extra safe and you never have to worry about your CPU temperature. You can clear the PROCHOT Offset box in the ThrottleStop Options window and clear the Lock PROCHOT Offset box too. Reboot your computer and have a look at that setting. If you see a lock icon, that means the BIOS has locked this setting. You cannot use ThrottleStop to adjust this setting if the BIOS has already locked it. 

This is what you will see when the BIOS has locked the PROCHOT Offset setting. 
Acer typically locks this so no surprise if your computer is locked.  




When you are playing a game, the Nvidia GPU is going to be active so it will be adding heat into your computer case. Only the CPU is active when running Cinebench so less heat. 

Instead of setting the turbo ratios to 35, you can try reducing the turbo power limits to what your cooling system can handle. This should allow the CPU to run faster during Cinebench.   

The settings that work best for you are totally up to you. Every CPU and every situation is unique.


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## joao0111 (Mar 11, 2022)

@unclewebb  Thank you so much for all the help and information provided.
I'll be testing different turbo ratios for different work loads. I'm glad to hear that my temperatures are normal and my laptop won't have a smaller lifespan.


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