I5 temp extreme while idle but low on load?

Hey, so I just built a new rig, specs are:
i5 2500K @ stock 3.7 (Runs at 1.6 when idle)
CM Hyper 212 Evo
Asus P8Z68V-LE
4 x G Skill 4GB 1600MHz 9-9-9-24-2N
Windows 7 64bit

At idle my Cores are running at about 27-30 C and in hour long Prime95 tests it runs around 50-55 C (measured by SpeedFan and RealTemp).
Now what is really confusing is that when idle, SpeedFan and CPUID Hardware Monitor show my "CPU" (Case temp I guess) as 85-90 C but under 40 C when in a Prime95 test.
This is consistent behaviour, I've done a few PC restarts and starting/stopping of the Prime95 test and the outcome is always the same. And the temperature changes from the idle to load ranges and vice versa within about 5 seconds after starting/stopping the tests.

Is that the programs not reading the sensors correctly, something is wrong with the sensor itself or is it possible that it is actually happening??

Thanks in advance.

EDIT: Also, if it is a case of just an incorrect reading, do those temps sound about right for this i5 at these speeds with a Hyper 212 Evo (using the fan and paste that came with it)? Or have I likely botched applying the Paste? (It's my first time)
8 answers Last reply Best Answer
More about temp extreme idle load
  1. CPU temp is great the other temp defies logic!
  2. Might possibly be related; Once every few boots at POST, I get a CPU Fan Error but it fixes itself within a few seconds of reporting the error. It is the stock fan that came with the Hyper 212 Evo.

    I'll check all my connections..
  3. Check the fan speeds, maybe at idle it slows it down too much(thus higher temps)? unlikely(since it should be temp and load based), but its all i got.
  4. While in the BIOS, CPU = about 30 C, CPU Fan = about 1000 rpm.

    In Windows I use Hardware Monitor and I get the following (all temps from the Mobo except Cores);
    Idle: CPU = 82 C, CPU fan = 950 rpm, Core Avg = 32 C (also AUX = 58 C, TMP = 32 C)
    Prime95: CPU = 37 C, CPU fan = 1375-1400 rpm, Core Avg = 50 C (also AUX = 50 C, TMP = 51 C)
    SYS always sits at about 26 C.

    EDIT: Oh and the CPU temp changes between 82 and 37 instantly after Prime95 is started/stopped. AUX, TMP, Cores, CPU Fan Speed all take a few seconds.
  5. I think the sensors are messed up. If the board actually seen that kind of temperature, the cpu fan would be maxed out.

    Core(die) sensors normally show too low at idle. not sure why your show very high, but i would guess the sensors are the problem.
  6. Best answer
    nothing to worry about

    common knowledge that thoes cpu temp programs dont work with that motherboard

    got the same board but different cpu. except i get 112oC in that program

    and 40 or so in bios

    well slightly different motherboard
    (asus p8z68 -vlx and i5 2400)

    dont worry about it
  7. shanky887614 said:
    common knowledge that thoes cpu temp programs dont work with that motherboard

    Ah okay. Looked around and the latest AIDA64 Beta has it fixed for this mobo so I downloaded it and yes, my CPU temp is now displayed as about the same as the core temps.

  8. Best answer selected by SuperPop.
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