CPU temps "on the die" or not?

[beverage]

I read people worried about temps, and what's ok, and what's not.

Then others come back, with things about if the temp is being taken on the die or not.

OK, so what exactly does this mean? Where is the "die" and what does it mean if the temp is being taking "on it"?

Also, what is the alternative way to take a CPU temperature, if it's not on the die, where is it taken?

How much hotter will "on the die" normally run than the other way, whatever that may be?

I'm just generally curious about temp readings, and the different ways to gather the same information, so any thing anyone has to offer would be greatly appreciated.

thanks

 

[randomboy]

As far as I know from reading the forums for the past few weeks, the "die" is the actual CPU chip mounted on the ceramic/organic/otherwise core. Die temps are taken from a thermistor built into/or close by the die I believe, whereas the other way manufacturers obtain CPU temps is from a thermistor that sits underneath the core and inside the socket on the mobo. Generally on die and socket temps can be anywhere from 10-25C differing from each other (I think 🙂). I'm pretty sure most of this is at least somewhat correct, its amazing what you can learn from just reading a few hours a day 🙂

Jeff

 

[beverage]

Well I guess the main reason I ask, is I have a Temp monitor that I bought aftermarket because my motherboard doesn't have onboard temp sensors. Following the Instructions, I used the included thermal tap, and taped the sensor directly on the bottom side of the processor. the very thin wires were then led between the pins, and the processor seated in the socket.

I'm curious as to if this installiation is "on the die" or "not"

Seems to me, it would be pretty hard to read temps from directly off the top of the CPU, since the heat sink is in direct contact with the hottest part of the CPU.

The temps I get from the underside of the CPU seem warm to me, and I'm just curious if I'm getting temps that people refer to as "about 10 to 15 degrees higher" than other temps (in which case I'd be ok), or if the temps I'm seeing are really the temps that would normally be the ones that ARE 10 to 15 degrees cooler (in which case i think i need a new HSF).

 

[randomboy]

The way you have it now, I think I'd compare to a socket reading. Thats how my ABIT KT7A was set up, the thermistor comes straight out of the board in the middle of the socket and comes up so that the tip of it is just a little higher than the top edges of the socket. So that way when you install the CPU on top of it, the thermistor is pressed right up against the bottom and it reads it that way.

 

[beverage]

so is that temp "normally hotter than the other" or "normally cooler than the other" ??

 

[SWScorch]

I just skimmed, so if I am on the wrong track, I apologize in advance.

Reading the CPU temp from the die gives you the exact temperature of the CPU, since the diode is located in the CPU itself. Only three motherboards that I know of can do this: Asus A7V333, and two Epox boards (cant remember their model numbers). Every other motherboard has a thermistor located underneath the CPU, in the socket, and so that reads the air temperature underneath the CPU. My A7V333 can read both, so using MBM5, I can see how much they differ. Right now, the socket thermistor reads 40C, and the die thermistor reads 49 C.

From what you describe, running the two wires between the pins of the CPU, you are doing the same thing as most motherboards do; you are not reading the die temperature, so you should up that reading by 10 degrees C or so to get a semi-accurate die temperature.

 

[beverage]

OK, so even tho the sensor is physically taped to the underside of the CPU, the temp i am reading is the "lower" temperature? Or should I assume it's maybe between the two, since it's neither physically in the CPU, nor in the air space below it.

 

[svidanag]

Your setup give similar readings to the in-socket thermistors on most mobos. It is in the same place, and the mobos thermistor are bent up and actually touch the cpu in most cases. Figure your readings are 10-20 degrees C lower than the die itself.