3 ms·
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 t
by msimpson 10y ago
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.
- ksk 10y agoThanks for explaining in detail.