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Practically, sure, you pretty much have to do whatever it takes to get it working. But its not like we're talking about trade secrets here. They simply have to release a coherent definition of what they consider a typical load.

I get your point, but nothing wrong in drawing attention to the specs being incomplete to the point of being useless.



> They simply have to release a coherent definition of what they consider a typical load.

Have fun getting AMD and Intel to agree on something.

> I get your point, but nothing wrong in drawing attention to the specs being incomplete to the point of being useless.

Vague or averaged is not useless.


What does Intel documenting their own specs have to do with AMD?


TDP is used by multiple manufacturers, so getting a "coherent definition" is going to take work. If you want to understand more about the thermal specs from only Intel. You can read their thermal guide:

http://www.intel.com/content/dam/www/public/us/en/documents/...


Sorry, I don't understand your point. Each vendor already defines it in their own way. The point of the article is that without proper guidance you end up guessing. I'm afraid the guide you linked to doesn't help much.

Intel confusingly tells us "TDP: Thermal solution should be designed to dissipate this target power level. TDP is not the maximum power that the processor can dissipate."

So according to Intel [1] - "The best way to measure a server’s power consumption is the power meter, an inexpensive tool that is plugged into the wall, and then your device, like a server, can be plugged into the power meter. The meter displays the wattage drawn "at the wall" and allows you to analyze the power consumption under a variety of different utilization levels.". Strange.

I was looking up docs on AMD. They seem[2] to kinda get it: "To allow optimal reliability of the AMD Opteron and AMD Athlon 64 processor-based systems, the thermal and cooling solution should dissipate heat from a processor operating at its maximum thermal power.". I could find some old docs[3] that did give the maximum power, but can't seem to find any on their recent CPUs.

[1] http://www.intel.com/content/dam/doc/white-paper/resources-x...

[2] ftp://ftp.sgi.com/public/Technical%20Support/Pdf%20files/AMD/26633_5649.pdf

[3] http://hackipedia.org/Platform/x86/AMD/AMD%20Thermal,%20Mech...


Refer to the following, taken from that guide:

  4.1 T_CASE and DTS-Based Thermal Specification Implementation

  Thermal solutions should be sized such that the processor complies to the T_CASE
  thermal profile all the way up to TDP, because, when all cores are active, a thermal
  solution sized as such will have the capacity to meet the DTS thermal profile, by
  design. When all cores are not active or when Intel Turbo Boost Technology is active,
  attempting to comply with the DTS thermal profile may drive system fans to speeds
  higher than the fan speed required to comply with the T_CASE thermal profile at TDP.

  In cases where thermal solutions are undersized, and the processor does not comply
  with the T_CASE thermal profile at TDP, compliance can occur when the processor power
  is kept lower than TDP, AND the actual T_CASE is below the T_CASE thermal profile at that
  lower power.

  In most situations, implementation of DTS thermal profile can reduce average fan
  power and improve acoustics, as compared to T_CONTROL -based fan speed control. When
  DTS < T_CONTROL , the processor is compliant, and T_CASE and DTS thermal profiles can
  be ignored.

  5.3.1 Intel ® Turbo Boost Technology

  Intel ® Turbo Boost Technology is a feature available on certain Intel ® Xeon ®
  processor E5-1600 and E5-2600 v3 product families SKUs that opportunistically, and
  automatically allows the processor to run faster than the marked frequency if the part
  is operating below certain power and temperature limits. With Turbo Boost enabled,
  the instantaneous processor power can exceed TDP for short durations resulting in
  increased performance.

  (http://www.intel.com/content/dam/www/public/us/en/documents/guides/xeon-e5-v3-thermal-guide.pdf)
This means that as long as you give the CPU a thermal solution capable of dissipating a thermal wattage equivalent to the CPU's temperature, at its case, when it reaches TDP, you're good. However, if you push the processor into Turbo Boost (like Atwood did with mprime), the CPU can exceed TDP for short durations. And, while all this is happening, the Thermal Control Circuit (TCC) is managing the thermal output by adjusting the clock, frequency, and input voltage automatically so the CPU stays away from operational limits. Therefore, if you intend to run this CPU under a sustained heavy load you must supply a thermal solution beyond TDP.

Intel literally spelled that out in this PDF which they linked from their TDP definition on every CPU specification page.

Now, in terms of power consumption. You must consider the entire system as the CPU is going to manage itself to fit its environment given the TCC. That is why Intel suggests you measure overall consumption for the server using a power meter as each implementation can yield different results. Therefore, what Atwood is doing is actually Intel's recommendation for considering actual power consumption. He, as I originally stated who knows how many replies ago, is making the mistake of directly equating power consumption to heat dissipation. When all you can really be sure of is that if a CPU consumes 1 watt of power it can dissipate up to the same in heat. But, as thermal dynamics will tell you, it will always be a bit less on the output as nothing is 100% efficient.

Therefore, all Atwood's test proves is an Intel® Xeon® Processor E5-1650 v3 has the potential to dissipate up to 250 watts of heat while in Turbo, given its recorded power consumption, in that specific computer configuration while running mprime. Nothing more, nothing less.

That is my point.


Thanks for explaining in detail.




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