13 Replies Latest reply on Jul 18, 2018 8:58 AM by Intel Corporation

    Current Limit Throttling in XTU

    ihsiao

      What is the definition of Current Limit Throttling in XTU?

      Does the core current really reach 120A?

      question.png

        • 1. Re: Current Limit Throttling in XTU
          Intel Corporation
          This message was posted on behalf of Intel Corporation

          Hello ihsiao,
          Thank you for contacting us regarding the Current Limit Throttling in our Intel® Extreme Tuning Utility (Intel® XTU); it will be more than a pleasure to assist you.
          Depending on the machine that you own, the readings of the values can change.
          In order for me to assist you better, please provide me with the .txt file that the System Support Utility will generate. To attach a file, you must click the “Attach” option on the bottom right-hand corner of the response box.
          https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows-
           
          I hope to hear from you soon.
          Best Regards,
          Diego S.
           

          • 2. Re: Current Limit Throttling in XTU
            Intel Corporation
            This message was posted on behalf of Intel Corporation

            Hello ihsiao,
            I was checking your case, and I just wanted to know if there is anything else that we can do for you at this time.
            Please do not hesitate on replying back if you need more assistance.
            Best Regards,
            Diego S.
             

            • 3. Re: Current Limit Throttling in XTU
              Shen#7684

              Hi Intel Team,

               

              Excuse me, so this issue has been resolved ? Because I have same issue in XTU(current limit throttling).

              Could you teach us how to check something and resolved it.

               

              And also attached the SSU info for you refer.

               

              Thank you.

              Miller Shen

              • 4. Re: Current Limit Throttling in XTU
                Intel Corporation
                This message was posted on behalf of Intel Corporation

                Hello Shen#7684,

                Thank you for contacting us.

                In order to assist you better can you please tell us exactly what the issue that you are experiencing is?

                As well, what’s the maximum setting that is causing the issue?

                I hope to hear from you soon.

                Best Regards,

                Diego S.

                • 5. Re: Current Limit Throttling in XTU
                  Shen#7684

                  Hi Diego S.

                   

                  When I using XTU in overclocking application and sometime happen the "Current limit throttling".

                  Could you teach us how to check something(BIOS setting) and resolved it.

                   

                  There is setting the "Turbo Boost Power, Short Power Max and Core IccMax" to maximum.

                   

                  擷取.PNG

                  Thank you very much

                  Miller Shen

                  • 6. Re: Current Limit Throttling in XTU
                    Intel Corporation
                    This message was posted on behalf of Intel Corporation

                    Hello Shen#7684
                    Thank you for your reply.
                    In this case, Current Limit Throttling refers to the limit of the processors before it starts to throttle.
                    Let us ask, are you trying to change that setting or to know what the limit is?
                    Regarding your inquiry, quoting your words: “Could you teach us how to check something(BIOS setting) and resolved it”, please go ahead and give us a longer/more detailed description of your issue so we can assist you better.
                    I hope this helps.
                    Best regards.
                    Diego S.
                     

                    • 7. Re: Current Limit Throttling in XTU
                      Shen#7684

                      Hi Diego S.

                       

                      Let us ask, are you trying to change that setting or to know what the limit is?

                           - Yes, I am keep doing, but it seems that there is no progress. When I run the XTU built-in benchmark sometime happen the "current limit throttling", so need your help.

                       

                      First step from the BIOS setting and unlock the current limit, so we want to know which one setting is associated with it. Thanks for you help.

                      擷取.PNG

                       

                      Miller Shen

                      • 8. Re: Current Limit Throttling in XTU
                        ihsiao

                        Hi Diego S,

                         

                        My PC specification:

                        CPU: i7-8700K

                        MB: MSI B360M PRO-VD

                        DIMM: crucial 8G DDR4-2400 UDIMM *2

                         

                        I set Iccmax from 70A to 120A, then run Prime95 Burn/In test (Small FFTs)

                        And I calculate the current by the TDP and voltage in XTU

                        Measurement data as below , Icore = TDP / Vcore

                        IccMax(A)MAX Core (GHz)CORE TDP (W)Vcore (V)Icore (A)
                        702.85450.85452.69
                        803.19580.91163.67
                        903.39680.94272.19
                        1003.59760.96179.08
                        1103.79860.99186.78
                        1213.89951.00894.25
                        1304.091101.053104.46
                        144.54.21201.084110.70
                        1504.291311.103118.77

                        I set IccMax as 70A, and Current Limit Throttling asserted when the actual current was 52.69A.

                        I set IccMax as 80A, and Current Limit Throttling asserted when the actual current was 63.67A. And so on...

                        It seemed that  Current Limit Throttling was not triggered by IccMax setting value.

                        Are there other conditions to trigger Current Limit Throttling?

                        • 9. Re: Current Limit Throttling in XTU
                          Intel Corporation
                          This message was posted on behalf of Intel Corporation

                          Hello ihsiao and Shen#7684,
                          Thank you for both responses.
                          I will escalate your case to gather further information regarding your request, this will cause a brief delay in our answers, however I will reach you back as soon as we have news.
                          I hope this helps.
                          Best regards.
                          Diego S.
                           

                          1 of 1 people found this helpful
                          • 10. Re: Current Limit Throttling in XTU
                            Hessam_7800gtx

                            I have the exact same issue aswell

                            Current limit throttle causes cpu to drop to 2.5 and sometimes even to 1.8 ghz

                            I have HP pavillion power 15 With i7 7700HQ  GTX 1050 and 8gb of ram

                            I tried contacting hp but they couldnt help me

                            current throttle only happens when i use my nvidia gpu to play games or run tests

                            you are my last hope i hope you can help me

                            thank you

                            • 11. Re: Current Limit Throttling in XTU
                              Kirill Katsnelson

                              Thank you for escalating the issue. I also always see the "Current limit throttling" on two workstations with Skylake-X CPUs, one 7820X, another 7960X. The former may be mildly overclocked, the latter is not at all, just the default configuration from the motherboard. In fact, none of the throttling or other flag type indications in HWINFO change during the event. I am attaching a graph screenshot from the second, the 7960X machine, if it can help. There is a correlation in the graphs with the CPU clock (x36 vs x33), and another possibly interesting one with another parameter, Active Core Count. HWINFO does not have an indication for it, either, but my guess it reflects cores C-states. The machine is constructed quite well, with decent cooling (the Noctua largest NH-14 dual-fan heatsink), and scores a bit above 1000 GFLOPs in the MKL linpack test (the quite recent one that came with the Parallel Studio XE 2018.2, and using AVX-512 instructions). This score matches (actually, even exceeds by about 5%) that reported by the HPC workstation builder Puget Systems, so I do not believe the CPU could be in fact throttling. And the reported power dissipation with linpack is around 250W, much higher than that under the XTU benchmark, ~175W (and the temperature at 250W did not exceed 71°C, so it's a damn good cooler!). Could it be that the reported throttling indication is incorrect?

                               

                               

                              I am also wondering where the tool reads the Active Cores (my guess it's derived from per-core C-state?)  and this pesky Current Throttling values. Cannot find them reported in any of the sensor-reading programs!

                               

                              Here's another observation, possibly notable. The Turbo table read by HWINFO is

                               

                              Turbo Ratio Limits - IA/SSE, Resolved:  44x (1-2c), 40x (3-4c), 39x (5-12c), 36x (13-16c)

                              Turbo Ratio Limits - AVX2, Resolved:    37x (1-2c), 35x (3-4c), 34x (5-12c), 33x (13-16c)

                              Turbo Ratio Limits - AVX-512, Resolved: 35x (1-2c), 33x (3-4c), 32x (5-12c), 30x (13-16c)

                               

                              When the linpack benchmark runs, there is a "hot" second half of the test run, apparently when AVX-512 instructions kick in at all cores. For these ~30s, the Current Throttling indicator in XTU is steady yellow and indicates throttling. When the [EDIT:added] XTU's own [/EDIT] benchmark itself runs, the Current Throttling is on when the multiplier drops from x36 to x33. The numbers are all in the 16-core column of the Turbo table above. So my thought was, could it be that XTU takes the normal Turbo drop in the clock multiplier for the indication of current limiting? There is no way the CPU can be throttling and churning 1 TFLOP/s at the same time, really...

                               

                              Here's a 'shot taken during the linpack run. The transition to the latest 1/3 of the timeline is when the benchmark goes into this "hot" phase, with TDP bumping up, clocks going down from x36 to the x30 AVX-512 value, and the "Current limit" turns steady on:

                               

                               

                              Size   LDA    Align. Time(s)    GFlops    Residual     Residual(norm) Check 44000  44000  4      53.853     1054.6021 1.997583e-09 3.677608e-02   pass Performance Summary (GFlops) Size   LDA    Align.  Average  Maximal 44000  44000  4       1054.6021 1054.6021 Residual checks PASSED

                               

                              Size   LDAAlign. Time(s)GFlopsResidual Residual(norm) Check
                              44000  44000  4  53.853 1054.6021 1.997583e-09 3.677608e-02   pass

                               

                              Performance Summary (GFlops)

                               

                              Size   LDAAlign.  Average  Maximal
                              44000  44000  4   1054.6021 1054.6021

                               

                              Residual checks PASSED

                              EDIT: The autoformatting seems seriously borked, cannot paste plain text without having it turned into mess

                              EDIT: Clarify the x33 is selected during the XTU's benchmark, not linpack (that one runs the initial ~30s at x36, last ~30s at x30).

                              • 12. Re: Current Limit Throttling in XTU
                                Intel Corporation
                                This message was posted on behalf of Intel Corporation

                                Hello all.

                                Thank you for waiting.
                                 
                                I would like to gather more information about the configuration you have on the computer to continue the investigation on the case.  Please attach to this thread the TXT file the Intel® System Support Utility will generate: https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility
                                Steps to save the report:

                                1. Run the utility.
                                2. Click on “Scan” to get the scanned system.
                                3. Once the scan is complete click on “next”.
                                4. Use the “save” option, save the report to your desktop.
                                5. To attach a file, you must click the “Attach” option on the bottom right-hand corner of the response box.
                                 
                                Regards,
                                Leonardo C.
                                • 13. Re: Current Limit Throttling in XTU
                                  Intel Corporation
                                  This message was posted on behalf of Intel Corporation

                                   
                                   
                                  Hello all,
                                  We just wanted to double check if you still need further assistance.
                                  Please do not hesitate on contacting us back.
                                  Best Regards,
                                  Diego S.