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  1. #1
    Jun 2014

    i7-4771 incorrect temperature reporting?

    I'm not sure how Intel Haswell temperature reporting is working but I'm noticing this weird behavior:
    On Haswell i7-4771
    Temperatures seem to extremely quickly (~15sec) spike up to 100c from a 42c idle when testing under load with CPU Burn...
    Tcase is not actually that hot. <66c which seems great! Measured externally, and also by resetting and going to the bios to see the reported temperature while stopping the CPU fan.
    Using Windows 7, CPUID HWMonitor or ASUS tool to see temps
    Tried and got identical results on 2 different motherboards. Z87 ASUS MAXIMUS VI GENE and Z97 ASUS GRYPHON. says Tcase 72c.

    Why am I getting wrong temperature reporting in Windows?
    - There is no way the temperature can physically spike that quickly given the mass if the heatsink.
    - If it did spike that quickly it would also not stabilize quickly at ~100c.
    - It feels like there is some type of "predictive" reporting based on load, because it also drops back to ~45c quickly!
    - Bios seems to show correct readings, or close enough to measured heatsink temp.

    For comparison, tested Ivy Bridge i7-3770 and package temperature increases normally/slowly to stabilize at 67c under full load with a low-end cooler.
    Obviously, it's understandable that there is a difference between Tcase and Tjunction (, but it should be nowhere near max allowed temp with proper cooling...

    Can someone with i7-4470 series CPU post reported temperatures after a few minutes under full load?
    Last edited by yanni5; 06-04-2014 at 05:57 PM.

  2. #2
    Aug 2004

    Re: i7-4771 incorrect temperature reporting?

    Temps in bios will usually read higher than idle in windows because power saving features are not activated.
    100c is max temp for cpu. clocks should slow to prevent over temps. ( cpu case temps may be used)
    Junction temps jump very fast if cpu sensor is located in a busy area of cpu. !00c may be the max that can be displayed

    Algorithms in BIOS determine temps shown, a bios update can change, correct, or throw off reported temps. Also updates to program.

    "The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
    - Albert Einstein (1879-1955)

  3. #3
    Jun 2014

    Re: i7-4771 incorrect temperature reporting?

    Thanks, I understand that BIOS temps will be higher than idle because of running at full clock speed.
    Let me rephrase the question,
    Why does Ivy Bridge show real temps but Haswell shows some type of predictive (fast changing, out of range) temps?
    By real temps I mean close-enough to heatsink thermometer.
    Actual Tcase cannot jump 20c in 2sec both up or down. (on cpuburn start and stop).
    So I think Intel is now "tweaking" temperature reporting because different burn programs cause distinctly different temp jumps. (not actual) And different motherboards seem to have a different range or lookup table. (Z87 45-100c, z97 47-80c) (both BIOS's show correct/actual temp)

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