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VR Thermal Limit

CAndr9
Beginner
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Hi, I have an Asus ROG notebook with a i7-4710HQ.

CPU is Haswell, so with the integrate voltage regulatore FIVR.

I OCed to 3.7 an all 4 cores and during stress test with AVX2 (AIDA64 FPU for example), after some minutes I notice some throttling caused by VR thermal limit.

The VR thermal limit alert is flagged by different software (ThrottleStop, HWiNFO64, etc).

My question: is it the VRMs on the motherboard or the integrated FIVR on the CPU package that hits the VR thermal limit?

Thanks in advance.

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idata
Employee
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Hello andreacos92,

Thank you for posting.

We cannot confirm which VRMs those tools are identifying since none of the mentioned are an official Intel tool. You will need to confirm with their repective developing teams, the answer could be related to the code they use to flag the VR thermal limit.

 

Amy C

Intel Customer Support Technician

Under Contract to Intel Corporation

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CAndr9
Beginner
4,375 Views

Hi Amy,

thank you for the reply.

Does exist any official Intel tool that reports VR thermal throttling? In XTU I can only see Thermal/Power/Current Throttling, but Thermal refers only on core temperature.

Thanks, Andrea

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CAndr9
Beginner
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Hi again, sorry for double post.

The HWiNFO64 developer told me that HWiNFO uses MSR 0x690 (MSR_INTEL_IA_PERF_LIMIT_REASONS) bit6 and bit22 to report VR Thermal Alert status, which is active in this case.

Can this help?

Thanks again

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idata
Employee
4,375 Views

Hi Andrea,

From my end there is not a specific software to read VR Thermal status. Our datasheet indicates that this can only be read with a software interface using processor Model Specific Register(MSR).

The HWiNFO64 developer told me that HWiNFO uses MSR 0x690 (MSR_INTEL_IA_PERF_LIMIT_REASONS) bit6 and bit22 to report VR Thermal Alert status, which is active in this case.

Can this help?

Yes, it does help. Actually, the MSR that sets the VR Therm Alert Status (R0) is MSR_CORE_PERF_LIMIT_REASONS 6. But, again I am not able to confirm if this specific MSR is the one used by the third-party tools in question. Maybe, with this piece of information you can confirm with their respective developing teams. You can check the MODEL-SPECIFIC REGISTERS (MSRS) here: https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf See page 2-210 Vol. 4 and Vol. 4 2-211.

You can check the Intel® Core™ Processors (M/H-Processor Lines) Datasheet, Vol. 1 here: https://www.intel.com/content/www/us/en/processors/core/4th-gen-core-family-mobile-m-h-processor-lines-vol-1-datasheet.html Intel® Core™ Processors (M/H-Processor Lines) Datasheet, Vol. 1

Amy C

Intel Customer Support Technician

Under Contract to Intel Corporation

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CAndr9
Beginner
4,375 Views

Thank you again Amy,

I've asked to the developer if HWiNFO uses the same bit you reported (MSR_CORE_PERF_LIMIT_REASONS bit 6).

If yes, can you tell me if this refers to the VR inside the CPU's FIVR or to the motherboard VRMs?

In the datasheet I didn't find this information.

Thanks again,

Andrea

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idata
Employee
4,376 Views

Andrea,

According to the Intel® 64 and IA-32 Architectures Software Developer's Manual Document, the MSR that sets VR Therm Alert Status (R0) for the processor is MSR_CORE_PERF_LIMIT_REASONS bit 6. This register is valid for the processor based on that document. It's possible that the motherboard's VRMs use different register and for that you will need to check with ASUS. I would recommend to wait for the HWiNFO response, they might be able to confirm if this is the register they use to report in their tool the VR Therm Alert.

Intel® 64 and IA-32 Architectures Software Developer's Manual: https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf

Amy C

Intel Customer Support Technician

Under Contract to Intel Corporation

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CAndr9
Beginner
4,376 Views

Hi Amy,

HWiNFO developer already confirms me that this is the register It uses to report in its tool the VR Thermal Alert.

So, do you confirm that we are speaking of the integrated VR in the Intel Processor?

Thank you again,

Andrea

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idata
Employee
4,376 Views

Andrea,

Yes, we are speaking of the MSR that sets VR Therm Alert Status (R0) for the processor.

You can confirm this in the Intel® 64 and IA-32 Architectures Software Developer's Manual page 2-210 Vol. 4 and Vol. 4 2-211.

Amy C

Intel Customer Support Technician

Under Contract to Intel Corporation

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idata
Employee
4,376 Views

Hi Andrea,

 

 

I hope this information was useful, and if you need further assistance let us know.

 

 

Amy C

 

 

Intel Customer Support Technician

 

Under Contract to Intel Corporation

 

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