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tomsHardware Please do this again with the latest processors

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  • Tom's Hardware
  • Processors
  • Flash
  • CPUs
  • AMD
  • Intel
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a b à CPUs
May 12, 2014 9:44:44 AM



Please do this with Intel Sandy,Ivy,Haswell and AMD FX series CPUs
Also do some research on thermal sensors since they aren't very accurate. I don't think any of your CPU reviews do temperature measurements.

More about : tomshardware latest processors

a c 211 à CPUs
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a b å Intel
May 12, 2014 10:13:10 AM

Ooh, that is old. I'm pretty sure most modern CPUs just shut off.

Measuring die temperature is really really tough, without using the built-in sensors. Extremely tough.
a b à CPUs
May 12, 2014 10:44:25 AM

Yeah that's old. Just want to know the current state of affairs.
The built-in sensors aren't accurate enough or something is probably hidden by Intel/AMD


From Core Temp:

"Intel defines a certain Tjunction temperature for the processor. This value is usually in the range between 85°C and 105°C. In the later generation of processors, starting with Nehalem, the exact Tjunction Max value is available for software to read in an MSR (short for Model Specific Register).
A different MSR contains the temperature data. The data is represented as a Delta in °C between current temperature and Tjunction.

So the actual temperature is calculated like this 'Core Temp = Tjunction - Delta'

The size of the data field is 7 bits. This means a Delta of 0 - 127°C can be reported in theory. In fact the reported temperature can rarely go below 0°C and in some cases (Core 2 - 45nm series) temperatures below 30° or even 40°C are not reported.



AMD processors report the temperature via a special register in the CPU's northbridge. Core Temp reads the value from the register and uses a formula provided by AMD to calculate the current temperature.
The formula for the Athlon 64 series, early Opterons and Semprons (K8 architecture) is: 'Core Temp = Value - 49'.
For the newer generation of AMD processors like Phenom, Phenom II, newer Athlons, Semprons and Opterons (K10 architecture and up), and their derivatives, there is a different formula: 'CPU Temp* = Value / 8'.

*CPU Temp is because the Phenom\Opteron (K10) have only one sensor per package, meaning there is only one reading per processor."
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May 12, 2014 7:57:41 PM

Hey there chimera201! I'll forward along your suggestion. Those videos were pretty darned cool back in the day.

I've asked Chris to take a look at this thread and chime in. :) 
May 12, 2014 10:00:09 PM

Would indeed be a fun experiment to try again with some unneeded CPUs. I'll see what we can do!
a b à CPUs
May 13, 2014 1:34:34 AM

Thanks for the positive response. The results might not be interesting this time around. All CPUs will shutdown when it hits the max temp limit. But it will be fun to see if one of them fails.

In case of AMD, people have reported that their CPU temperatures measured by third party programs like HWMonitor aren't correct. People have got lower temp readings than ambient temperature. And there is no temperature info on AMD's site. Intel's calculation of CPU temperature (Tjunction - Delta) seems logical enough. But AMD's calculation seems kind of funny - (offset by 49), (divide by 8) without any further explanation. Starting with AMD OverDrive Ver 4.3.1.0690 instead of displaying CPU temperature, AOD will report Thermal Margin. Thermal Margin indicates how far the current operating temperature is below the maximum operating temperature of the processor. How much accurate is this? Has AMD's thermal design gotten better or not?
!