So what is the consensus on AMD temperature reporting?

[Ketchup]

I don't post in this subforum too much (usually in Computer Help), but a couple weeks ago we were having an interesting discussion in here about an AMD chip reporting temps. I think we (at least I) came to the consensus that only one out of a half dozen programs were giving him accurate CPU temp numbers. This was on a laptop.

To you other AMD guys out there, have you noticed this as well?

It has been several years since I had an AMD chip (in which I cared about temps), but I seemed to be getting reasonable numbers at the time.

Here is the thread:
http://forums.anandtech.com/showthread.php?t=2334251

 

[Ketchup]

So nobody else has had a problem with this?

 

[tarmc]

I cant remember what app I use on my x2 3800, but I have noticed that the temps do fluctuate very erratically

 

[bgt]

Never have a prob. with my 8350. Using speedfan for years now and also no probs.

 

[Maximilian]

From what i can tell only realtemp and coretemp are any good, all the other temp programs are really hit and miss...

 

[Ketchup]

Ah, ok. Does AMD have an in-chip temp sensor like the Intel chips do?

 

[Rvenger]

Nope. External sensor

 

[Ketchup]

Nope. External sensor

Ah, well that makes sense. I do think it's funny that back when I really cared about temps (I am talking about over a decade ago, and to the degree) all we had were the external sensors. Now that we have internals, as long at it's within 10 degrees of what other people are seeing, I don't really care.

 

[Phynaz]

You can't get an accurate temp reading because AMD hasn't published their sensor offsets. It's been this way for something like a decade.

 

[BallaTheFeared]

AMD (last I checked, meaning Phenom II) uses an algorithm that reports low at low temps and gets more accurate as you heat up.

Which is why AMD can idle below ambient.

 

[bononos]

Ah, well that makes sense. I do think it's funny that back when I really cared about temps (I am talking about over a decade ago, and to the degree) all we had were the external sensors. Now that we have internals, as long at it's within 10 degrees of what other people are seeing, I don't really care.

AMD cpus do have internal temperature diodes. I think they all had them since the Athlon XP. But back then it was something new and motherboards didn't have temperature sensor chips to interface with the internal chip sensor and report temps to software utilities or maybe the temperature sensor chip wasn't compatible with the internal diode (I forget).

The problem is that AMD doesn't report actual on-die temps but some non-linear scale which is converted to temps or not, which is why AMD seems to report abnormally high/low/-ve temps, because those aren't temps that you are seeing, or maybe the conversion formula is bad.

http://www.overclock.net/t/1139726/amd-fx-bulldozer-piledriver-owners-club/4800#
The support ticket response says that the bulldozer internal diode is off die but somewhere else on the package. And there is another backup thermistor on the cpu socket.