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ACPI GPU overheating
#1
Hi everyone,

I was referred to the HWinfo program by nephew after my sons computer started to fail when he was using Photoshop CC. The symptoms have been unexpected shutdowns for no reason and the extreme slowing up of Photoshop to the point where it is unusable. The symptoms have been getting worse over the last 3-4 weeks. It was suggested that it may be an overheating issue and I was referred to HWinfo to enable me to monitor the temperatures of the various components. I did this and noticed that one temperature seemed excessively high. Under the ACPI sub heading there is a reading entitled GPU which starts at 80 degrees C and has been as high as 106 degrees C before the computer shut itself down. However later in the monitoring list there is a whole section under the sub heading of GPU. The temperatures relating to GPU in this section would seem normal.

I have updated the BIOS, clean installed the drivers for the graphics card. I have also stripped down the computer to ensure nothing was blocked with dirt. It was fairly clean and sadly made no difference. I have avoided reseating the heat sink as I am worried about making the problem worse if the ACPI GPU has nothing to do with the graphics card. I have attached a screen capture of the HWinfo summary and the part of the monitoring page showing the ACPI GPU temperature and the other GPU readings.

I am also concerned by the GPU fan only running at 30% although that may be because the Graphics card is cool enough?

So 2 questions

1.What does the ACPI GPU temperature refer to? Is it the graphics card or something else

2.Any suggestions as to what I might try next?

Thanks in anticipation.......


Attached Files Thumbnail(s)
       

.csv   post ati driver install.CSV (Size: 109.2 KB / Downloads: 1)
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#2
Those ACPI values are not 100% guaranteed to have correct names. The problem is, that they relate to some internal values in the machine and only the vendor knows exactly their meaning. The internal name for the ACPI GPU value is "VGAT", which might suggest it's the GPU temperature, but you're right - when looking at internal GPU temperatures, they look OK. So I believe this value might be something else, maybe some voltage regulator. But I'm afraid, only DELL knows exactly.
I have checked the attached sensor log and noticed another thing - if you look at the "On-Demand Clock Modulation" values, they start to fall down when a certain temperature is reached. This is a common way used by notebook manufacturers to throttle the CPU. But it's very strange, that it falls down even though the CPU temperature looks OK (~53 C). At the end of the table I can see On-Demand Clock Modulation=25%, which means, that your CPU is running at 25% of performance only, which explains the slowdown you experience. Even though none of the other temperatures (except VGAT) indicate a critical thermal situation.
So there's either some component that's really overheating (VR maybe?), or there's a bug in the firmware logic for thermal management. In either case I suggest to contact DELL for an advice or repair. Another alternative is to look at some forums (Tech|Inferno for example) if there are other users of this notebook model experiencing a similar behavior.
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#3
(09-22-2014, 07:21 AM)Martin Wrote: Those ACPI values are not 100% guaranteed to have correct names. The problem is, that they relate to some internal values in the machine and only the vendor knows exactly their meaning. The internal name for the ACPI GPU value is "VGAT", which might suggest it's the GPU temperature, but you're right - when looking at internal GPU temperatures, they look OK. So I believe this value might be something else, maybe some voltage regulator. But I'm afraid, only DELL knows exactly.
I have checked the attached sensor log and noticed another thing - if you look at the "On-Demand Clock Modulation" values, they start to fall down when a certain temperature is reached. This is a common way used by notebook manufacturers to throttle the CPU. But it's very strange, that it falls down even though the CPU temperature looks OK (~53 C). At the end of the table I can see On-Demand Clock Modulation=25%, which means, that your CPU is running at 25% of performance only, which explains the slowdown you experience. Even though none of the other temperatures (except VGAT) indicate a critical thermal situation.
So there's either some component that's really overheating (VR maybe?), or there's a bug in the firmware logic for thermal management. In either case I suggest to contact DELL for an advice or repair. Another alternative is to look at some forums (Tech|Inferno for example) if there are other users of this notebook model experiencing a similar behavior.

(09-22-2014, 07:21 AM)Martin Wrote: Those ACPI values are not 100% guaranteed to have correct names. The problem is, that they relate to some internal values in the machine and only the vendor knows exactly their meaning. The internal name for the ACPI GPU value is "VGAT", which might suggest it's the GPU temperature, but you're right - when looking at internal GPU temperatures, they look OK. So I believe this value might be something else, maybe some voltage regulator. But I'm afraid, only DELL knows exactly.
I have checked the attached sensor log and noticed another thing - if you look at the "On-Demand Clock Modulation" values, they start to fall down when a certain temperature is reached. This is a common way used by notebook manufacturers to throttle the CPU. But it's very strange, that it falls down even though the CPU temperature looks OK (~53 C). At the end of the table I can see On-Demand Clock Modulation=25%, which means, that your CPU is running at 25% of performance only, which explains the slowdown you experience. Even though none of the other temperatures (except VGAT) indicate a critical thermal situation.
So there's either some component that's really overheating (VR maybe?), or there's a bug in the firmware logic for thermal management. In either case I suggest to contact DELL for an advice or repair. Another alternative is to look at some forums (Tech|Inferno for example) if there are other users of this notebook model experiencing a similar behavior.

Hi Martin,

thank you very much for your comprehensive reply - extremely useful. The only further question I have is that you suggest the component might be the VR - what is that? I think I will post the context of this thread up to Dell to see if they can offer anything up but previous experience with Dell customer support has not been great!

Thanks again,

Rob
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#4
Hi Rob,

VR = Voltage Regulator. This is a circuit which supplies voltage to various components and usually runs at temperatures higher than other circuits.
But it might be something else, or a bug in the firmware logic...

Martin
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#5
(09-22-2014, 10:58 AM)Martin Wrote: Hi Rob,

VR = Voltage Regulator. This is a circuit which supplies voltage to various components and usually runs at temperatures higher than other circuits.
But it might be something else, or a bug in the firmware logic...

Martin

Thanks Martin - will post to Dell and Tech Inferno

all the best

Rob
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