# PL 1 limit red on Throttlestop



## Tonny212 (Jun 30, 2020)

Hello, recently figured out what Throttlestop was and decided to do an undervolt.

I have an i5-8250U laptop, Dell Inspiron 15 5579. I undervolted CPU core and cache to -135mv, and have the System auto fan speed set. At max fan speed, 5600RPM, and running the benchmark, the cpu slowly crawls its way, and as soon as it touches 100C, PL 1 limit kicks in and it is limited down to 15W at 2.7GHz, not at full boost, 3.4GHz. Any way to force it to run at full speed, or just thermal throttle instead?

More info: On the right in FIVR, it shows my offset is +0 on everything, even if i have -250mv on CPU core. Does this mean absolutely nothing is changing?

And also, I set my PL 1 limit to 35W, and it hits 35W but after like 5 seconds or so for some reason, PL1 limits power usage down to 20W even though my limit is set to 35W.

UPDATE: I downgraded my laptop bios to 1.12, from 1.13. This fixed the undervolting, so now it undervolts. But anyway, my CPU is able to go at 30W for like 5 seconds, but then PL1 limit kicks in, throttles it down to 15W and slows it down to 2.50GHz. I enable that patch everyone said to enable, and it now throttles it to 23W at 3GHz. Better, but not as good as I want, as I know this is capable of full turbo indefinitely. The cooler can handle it.


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## unclewebb (Jun 30, 2020)

Try posting a screenshot of ThrottleStop with Limit Reasons open while your CPU is loaded. A screenshot of the TPL and FIVR windows is useful information too. It is difficult to guess what you should try without seeing what is holding you back. 

I use www.imgur.com for free image hosting but you can also host images here. The little image icon to the left of the happy face should work.


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## Tonny212 (Jul 2, 2020)

unclewebb said:


> Try posting a screenshot of ThrottleStop with Limit Reasons open while your CPU is loaded. A screenshot of the TPL and FIVR windows is useful information too. It is difficult to guess what you should try without seeing what is holding you back.
> 
> I use www.imgur.com for free image hosting but you can also host images here. The little image icon to the left of the happy face should work.


Alright, I uploaded them to Imgur. here: 



http://imgur.com/a/oZ4Iut4


Also, I heard it could be caused by voltage regulators overheating?? I could figure that out, i have a temp probe I can scan them with


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## unclewebb (Jul 2, 2020)

When your CPU is throttling, ThrottleStop shows POWER in red and Limit Reasons shows PL1 glowing red. It is the long term turbo power limit that is holding you back. Power consumption is just under 24W. This means your laptop is ignoring the 40W turbo power limit request that you set in ThrottleStop. Some laptops do this. Long term they will set a lower power limit internally in a separate register and there is usually nothing you can do about it.

Try setting the turbo time limit to the default value which is 28 seconds. Setting it to 3, 670, 016 seconds is an awfully long period of time. Just because you can set ThrottleStop to this value does not mean you should.

After testing that, try checking the TDP Level Control option and set that to 0, do a test and then set it to 1 and 2 and do some more tests. This usually does not accomplish too much but there are no other options.

24W is better than 15W. Next time you are limited to 15W, open up Limit Reasons and see if the limit is temperature or one of the power limits.

Edit - If you want to use Speed Shift, you have to check this option in the TPL window. Most laptops enable this automatically in the BIOS. Your laptop does not.


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