Intel TAT / CoreTemp / IDCC all different temperatures....

[fgw]

You mean like this?




It would be seriously great if it is.

It just seems like it's based on the same Tjunction value set by the software, which is the cause of this argument, but it just reads in reverse

jumping in here as i requested this feature (show delta to tjunction temp) over at the coretemp development forum.

anyway, YES this is the feature!

all temp monitoring software which is using dts (digital thermal sensor) is reading the temperature from a register within the processor. this register holds the plain dts value showing the temperature offset to

• tjunction temperature for mobile processors
• thermal control circuit (tcc) activation temperature for desktop and server processors

absolute core temperatures are simply calculated by the following formula:
core temperature = tjunction - dts or core temperature = tcc - dts

it doesn't really matter if you call it tjunction or tcc as in both cases this temperature is just an assumption made by the writer of the monitoring software. the value used in the formula counts, not the name ...

accuracy depends on the correct chosen value for tjunction or tcc which is obvious by looking at the above formula. as intel does NOT make this values available to public nor is this value readable by software, software developers have to guess what value should be used for tjunction.
thats the difference in coretemp 94 and coretemp95! both versions of coretemp simply use different values for tjunction, either 85c or 100c. thats why readings in coretemp might be off by 15c on certain processors.

using the delta to tjunction temp instead, displays plain dts readings without conversion to an absolute temperature value thus being completely independent from probably wrong selection of tjunction value in monitoring software. using this feature in coretemp makes you completely nonindependent from tjunction and gives correct values on ALL processors supporting dts.

this delta to tjunction temp just says how many degrees is the processor away from tcc activation (throttling) and thus looks reverse to regular coretemp readings: large dts means cool processor, small dts means hot processor!

the last question here: what is a save dts value?
well as with regular coretemp readings this depends on the environment your processor is running in. my very personal rule is as follows:

• running on high vcore, which to me is everything above 1.5v, i would try to keep dts above 30c. (this translates to about 55c in coretemp94)
• on lower vcore, a dts value above 15c should be fine and easy achievable. (70c in coretemp94)

this assumptions take into account that higher vcore results in higher current and thus in higher current density which besides temperature is the most responsible parameter for reliability or failures due to electromigration. reducing operating temperatures maintains reliability even if current density (vcore) is raised.
the general rule is roughly: decrease temps by at least 20c for every current density increase of 100%! yes, there is some safety margin in my personal rules.

again, this is my very personal opinion gathered from reading through a lot of documents on this issues ...