CoreTemp0.96 - M0 stepping C2D Tj Max??

C

commodore

Limp Gawd
Joined
Dec 29, 2002
Messages
297
Not sure if this is in the right section but it is to do with overclocking. Many users with M0 stepping C2D's have reported higher temps than usual on [H]ardforum, apart from many others.

After lapping the IHS and my Tuniq Tower (which i thought were making very poor contact) i'm getting only 3'C lower than before on my M0 stepping E4500.
@2.2Ghz (stock 1.28 Vcore) -->Core Temp 0.96
IDLE: 44'C
LOAD: 66'C
@3.3 (1.464 Vcore) -->Core Temp 0.96
IDLE: 49'C
LOAD: 81'C

Note that Core Temp 0.95.4 assumes a Tj Max of 85'C and reports ~ 15'C lower values consistently THROUGHOUT for my M0 stepping E4500.

So, after a lot of reading up on the Tjunction Max issue for M0 stepping C2D's i'm not convinced that the Tj Max = 100'C is correct. In another forum a user justified the Tj Max =100'C value by confirming the same with the throttling temp of ~ 95'C , while assuming that Core Temp 0.96 is reporting accurately before-hand.

Now, doesn't Core Temp read the Delta to Tjunction Max value from the CPU and then calculate the Tjunction temp.? So basically its result is based on the Tjunction Max value.

where, Temperature = Tjunction Max - Delta (DTS value)

If you take a Tjunction Max of 85'C the throttling temp. is bet. ~ 80-85'C , above Tcase max of 73.3'C by a delta of ~10'C which is dead on for the M0 stepping!

..or so i think.

NOTE: Check this link about Core Temp measurement method
http://www.overclockers.com/articles1378/
 
Simple answer?

Check the "show delta to Tjmax" option. Don't worry about the actual temp, just as long as you have a delta.
 
Never said i was dead right did I??? ..yet your answer make no sense..

The "show delta to Tjmax" option takes into account a 'fixed' Tj max value doesn't it? ..else how is it possible to to give the calculate the delta in the first place?? :rolleyes::rolleyes:

If there is someone out there who can give me a surefire explanation why i am wrong then great!!
 
Because you do not understand the FIRST THING about how a DTS works.


Each DTS reports a number, which is the "delta to Tjmax." The chip is programmed internally with its Tjmax. So, REGARDLESS of whether it is an 85 C or 100 C Tjmax processor, the DTS will ALWAYS read the number of degrees left to Tjmax. SOFTWARE is translating it into a "useful" temperature. But if you understand the design of the system, you don't need it translated.


So, if you see delta to Tjmax = 20 -- that means you have 20 degrees until the processor executes a PROCHOT# instruction.

Fuck knowing what the Tjmax actually is. It doesn't matter. All that matters is this:

In all implementations the IA21_THERM_STATUS[22:16] value is relative to PROCHOT assertion and not an absolute temperature.
Click to expand...

As long as you stay below PROCHOT# you are fine. The CPU won't force a shutdown until you are another 20-25 C past PROCHOT# assertion according to the documentation.




So, to use the DTS as they were designed, you need to check the "show delta to Tjmax" option.
 
True ..the Delta to TjMax is always the same, for TjMax =85'C or 100'C .. thats straight from the DTS and not what i am disputing.

Core Temp 0.96 assumes a TjMax =100'C for all M0 C2D's which i think is wrong. A lot many users are concerned with the higher temps by +15'C being reported by this utility. Thats why the post and the explanation.
 
Although it has been said the Tjunction Max is 100°C I have never seen an official Intel specification that says this so who knows. I'm not sure where they are getting that from because as far as I can tell the official Intel processor datasheet does not list the Tjunction Max.
 
Intel has no official specs for Tj Max that have been made public..

At least the site admin @ Core Temp forums tends to agree with me on disregarding thermal throttling test as evidence for Tj Max..
http://www.alcpu.com/forums/viewtopic.php?p=1497#1497

So M0 rev/stepping users dont lose heart at the high temps ..stick to the delta to Tj Max value (DTS value) for reference like rainman said and you'll be fine!! ;)
 
Yeah, the problem is on some systems like Linux I don't have any applets that show the raw DTS value. Therefore I have to do the best I can based on what I know.

I have gone back and forth on the issue but at the current time I'm thinking these chips they are saying have a 100°C Tj Max are actually closer to 85°C. This would make so much more sense because when I check every temperature in my system when it's cold (including hard drives, system temperatures, etc.) they will all be about the same when using a Tj Max of 85°C. Using 100°C makes the CPU way, way hotter than everything else and that just doesn't make any sense because I have never had a system behave like that ever.
 
I am please to see so much correct info about DTS and how the "core temp" number is presented.

I have my grumpy posts too, but lets play nice. :D

Some of the newer chips have a 105C Tj even. Leave it to Intel to drive us insane (only 16 new cpus to learn weeeeeee !!!! ).

Look around and see if you can find a Linux utility that will read CPU MSR's.( Model Specific Register) or CPU registers in general. If you can find one here is how you can read the Delta to Tj directly from the cpu. I think you are probally able to translate the basic idea into penguineese, the critical regester address etc. are in the post.

http://www.hardforum.com/showpost.php?p=1031080147&postcount=5
 
If you wanted to, you could probably underclock the heck out of the processor, undervolt it as low as it can safely go, crank up your heatsink fan to the max, and then check what temp is reported. Severly underclocking like that should bring your core temp down to near ambient temps. If the temp reported is lower than ambient, then you know that coretemp is wrong.
 
You must log in or register to reply here.
Back
Top