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Power Limit PL1 resets after ~10 mins

tsro
Beginner
6,832 Views

I have an i7-6600U and use XTU 6.2.0.19. After setting PL1 to 20W either in the app or through the command line it does not throttle due to PL1, however, after a given time, I'd guess 5-10 minutes, it resets to 10 watts no matter what. If I set it to 20w and let it idle it resets after some time. The same happens if I stress test it. Actual PL1 is read with HWiNFO, but the fact that it has reset is also verified by that it starts to PL1 throttle. Then, if I reapply PL1 to say 19 or 21W, it stops throttling for some time until it resets again. I don't think that CPU or GPU voltage offsets resets but I'm not sure how to really verify that.

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idata
Employee
3,632 Views

Hi,

 

 

Please provide steps to replicate the issue. These steps are very crucial to finding the root cause and fix.

 

A screenshot to illustrate the issue is a huge plus. A video of the failure is even better!

 

 

Looking forward to hearing from you.

 

 

Allan.
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tsro
Beginner
3,632 Views
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idata
Employee
3,631 Views

You are currently running an Intel® i7-6600U, this is an ultra-low power processor, locked processor. Altering turbo boost settings may cause some issues with the actual processor frequency and power usage.

 

I just tested by changing same settings on my demo processor and I had the system restarted several times. I believe this is because we both have ultra-low processor model.

 

 

Allan.
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tsro
Beginner
3,631 Views

The system housing my 6600U is fully capable of handling 25 watts sustained load. Forcing PL1 to 25 watts with a script applying PL1 to 25W using XTU through the command line every 10 seconds or so causes no issues. The problem is first and foremost to disable whatever it is that resets the power limit and secondly to fix XTU so that it reports actual PL1 limit. As you can see in the video the reported PL1 is not correct.

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idata
Employee
3,631 Views

I have reviewed this situation and I would like to have additional information about your system configuration. Please run the following utility and attach the results.

 

 

https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility Intel® System Support Utility

 

 

Looking forward to hearing from you.

 

 

Allan.
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tsro
Beginner
3,631 Views

Here it is, thanks for taking a look.

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idata
Employee
3,632 Views

Thank you, for the information.

 

I will update this thread as soon as I get news about this matter.

 

 

Allan.
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idata
Employee
3,632 Views

Thank you for your patient, I just received some information in regard to this power limit issue.

 

There are some computer BIOS with CPU Power Management to set the Power Limit 1 Power to a specific maximum number which XTU will read it form there. Please try to access the BIOS and adjust configuration.

 

 

Allan.
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idata
Employee
3,632 Views

I was wondering if you still need assistance with the issue you previously reported on this thread.

 

 

Allan.
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tsro
Beginner
3,632 Views

In all tests, CPU Power Management has been disabled, with SpeedStep and Adaptive Thermal Management set to Max Performance and power cable plugged in.

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idata
Employee
3,632 Views

Hi,

 

 

Thank you for the feedback. Let me investigate further. I will update this thread as soon as I get news about this matter.

 

 

Allan.

 

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idata
Employee
3,632 Views

Hi todda7,

 

 

Thank you for your patience.

 

 

As per the video shared, we were able to see that PL1 value is not resetting in XTU and you are using another tool called "HWiNFO64" to read the values from BIOS. There, we can see that PL1 value is resetting to 10.

 

We checked in BIOS directly and PL1 value is reflecting correctly as tuned in XTU (it is not resetting).

 

We also tried downloading HWiNFO64 tool but after installing we are not able to see PL1 control in the tool.

 

And throttling is observed when PL1 and PL2 are tuned to low value (~25).

 

We would like to have further details about the value of PL1 directly in BIOS when HWiNFO shows 10. Please take a picture of it.

 

 

Please check the following steps of the PL1 value in BIOS directly.
  • Restart the computer and enter the BIOS by pressing F2.
  • Go to Intel Advanced Menu->Power & Performance->CPU – Power Management Control->View/Configure Turbo Options
  • In Current Turbo Settings section we can see the current value of PL1 and PL2.
  • If PL1 and PL2 are disabled. There will be option "Power Limit 1 Override", Enable it to enable PL1 and PL2.
Let me know if you need further assistance with your Intel product, I will be glad to assist you.

 

 

Allan.
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idata
Employee
3,632 Views

Hi todda7,

 

 

Let me know if you need further assistance with your Intel product, I will be glad to assist you.

 

 

Allan.
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tsro
Beginner
3,632 Views

There is no option for configuring Turbo Options in the BIOS of the Thinkpad X1 C4. I can't imagine it being enabled in very many consumer laptops with U-processors.

Furthermore there is no need to know the value of PL1 in the BIOS directly, since Power Limit Throttling is observed in XTU which implies that the power consumption is limited by PL1. Power Limit Throttling disappears upon readjustment (higher OR lower) of PL1 hence PL1 has been automatically reset. My issue is not that PL1 is incorrectly reported by XTU, but instead that PL1 is automatically lowered after some duration of sustained load which in effect causes sub-optimal system performance even though the cooling system is capable of handling the sustained thermal output.

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idata
Employee
3,632 Views

Thanks for the information.

 

 

This reset PL1 issue seems expected due to BIOS constraints. The BIOS appears to be locked by your computer manufacturer, I recommend http://www3.lenovo.com/sg/en/contact/ contacting Lenovo for possible pre-production BIOS or to get more information about their locked BIOS.

 

 

Allan.
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pzhu0
Beginner
3,632 Views

I have the same problem as yours, on my HP 840G5 Notebook.

And worked around it by disable DPTF in BIOS.

Not sure if this will work for you.

 

A quick reference guide is provided by Bonnom in https://techtablets.com/forum/topic/power-limit-throttling/

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