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I uploaded it here.
or at least some thing would smell like smoke :DQuote:
Originally Posted by Dua|ist
LMAO.....intel had stated each cpu is individually calibrated so that throttling will not occur below tcasemax, meaning each tjmax is adjusted up or down ? 5 ?10C etc. and also sensors have error even at tjmax.
My IR gun gives exact same temp in past when I had access to very accurate surface probe temp (from wifes workplace) so it is accurate.
Pic 1 shows E6850 corrected tjmax (in red) and temps that would be displayed. So tcase is ~10C hotter than core temp....mmmmmm ok
Clearly using tjmax of 80 on my E6850 would give at least 10C too low temps.
Pic 2 shows E8400 corrected tjmax (red) and temps that would be displayed. So tcase is 5C cooler than core temp...plausible, but now no longer provable.
i7 supposedly has reasonably accurate sensors. But for 45nm and 65nm I am adding 2-4C (gradient at idle UC plus increased grad from no heatsink) to what I get with IR gun at DTS=0 and calling it a day...clearly using tjmax's provided by intel can give ridiculous errors from combined "individual calibration" and "sensor error".
The IR measured difference between my E6400 - B2 and my E8400 - C0 is 10C. According to Intel's new document, the difference is actually 30C.
Edit: Intel calls these values Target TJ which don't seem to have too much to do with actual TjMax.
After the August announcement I thought that for a lot of users, using the Intel Target TJ as TjMax might not necessarily result in more accurate core temperatures. After this announcement, I can state as a fact that using the Intel specified "Target TJ" as TjMax for your E6x00 B2 processor will result in reported temperatures that aren't even close to accurate. These new facts go against any real world testing that's been done by rge or myself and makes both of us wonder how accurate the August news release really was. :shrug:
Maybe this means I need to run out now and buy a Core i7. Naah, they can keep them. :)
Edit: I re-read the document and they seem to be calling this number Target TJ. My opinion is that if users use Target TJ as TjMax then they will end up with some very unbelievable core temperatures. My E6400 is a good example:
http://img521.imageshack.us/img521/3748/newtruthqr0.png
In my 11C basement, it would be reported as running at minus 6C. Not that bad for an air cooled processor! I definitely recommend not using Target TJ as your TjMax value. Using Target TJ as TjMax for the 45nm processors might be questionable as well. Some 45nm processors will likely be reported a couple of degrees on the high side but if you do a RealTemp calibration then even if TjMax is off by a couple of degrees, your reported temperatures from 25C to 65C will still be reasonably accurate. This new info isn't going to help us out any.
Page 13 of the new Intel IDF bible says:
"The values listed for TJ Target are not specifications."
Hello there,
It looks like they didn't disclose anything. Just a point of reference for further research. A target Tj (desired?) which is individually calibrated for each unit. You can stick about that point, but merely can set it as a fixed value in RealTemp or any other monitoring software...
And... I don't see any information about PDC 2000 series, so I'm still stuck with my L2 stepping. Seems I'll have definitely downclock and undervolt, put the HS off and measure the Tcase with a multimeter...
And as for multimeters, guys... I don't have an IR gun and I will have to use my multimeter for temperature measurements. But I am afraid of doing that. AFAIK the temperature probes have something in common with conductivity. Do you think it's safe to place such a probe on an IHS?
Suckers buying TECs and chillers...results with just PA 120.3 w/3 nexus fans at 1000 rpms. ambients 26-27C.
pic1
E6850 3.9ghz 1.475 vcore bios, 1.44 load vcore,
full orthos load at 40C...only 10C above intake ambients even with 8800 ultra in the loop...ignore speedfan cpu temp of 57C...clearly an error:rofl::rofl:
pic2
E6850 4.3ghz 1.6 vcore idling at -7C in 26C ambients.:rofl::rofl::rofl:
It is fine to touch a multimeter probe on IHS...but you will not get accurate temps that way. I bought one, paid extra for calibration, only to find that out. There are surface temp probes for few thousand...little expensive for the task...but thermocouples are going to read way low as most of it is measuring temp of air when touching to a surface. Which is why intel embeds them in the IHS, and even then have to calibrate them.Quote:
Originally Posted by mikaelc
I'm really confused now what values to use for the DTS reading offset.
Tj Target probably not so why do they publish these values? Is Tj,max different from that Tj Target (never seen such a naming in documents)?
Moreover:
- the inaccuracy of DTS readings raises at lower temps
- certain CPUs report invalid DTS temperature below 50 C
- DTS was never meant to be used for temp reporting - just to catch the hot point (value -> 0)
Is it really usable, or better forget all DTS on CPUs prior to Nehalem ?? :shrug:
The first bunch of Core i7 is just more of the same.
"The PROCHOT# activation temperature is calibrated on
a part-by-part basis and normal factory variation may result in
the actual activation temperature being higher than the value
listed in the register."
Software will be able to read some sort of Target TJ value from a register but that's not a TjMax value so there's no way to convert that to an accurate core temperature. These new sensors will also have slope error, less than the current 45nm processors I assume, but it's still there.
"Future processors may report temperatures in °C"
Looks like the enthusiast community will have to wait for the next generation after Core i7 before they'll ever know something simple like what temperature their CPU is running at. :(
So then, if the Target Tj is not Tj Max, then what the heck is it? :confused: Damn you Intel!
EDIT: Remember this? http://www.overclockerspulse.com/new...tjmax-for-all/
Looks like Mr. Inkley was being a bit misleading.
randomizer: Why not get your friends over at Tom's to download this guide:
Thermal and Mechanical Design Guidelines
http://download.intel.com/design/pro...nex/317804.pdf
Tell them to head to Appendix D so they can learn how to carve up the IHS of an old CPU that they must have in a drawer somewhere. Then they can run a thermal couple to the geometric center and at least get a Tcase reading with the heatsink attached. It would be a very interesting article to see how that temperature compares to and tracks core temperatures from idle to full load while using a variety of different programs and different loads.
In the good old days Tom's Hardware was always doing cutting edge stuff like that to get to the bottom of issues. With over 100,000 downloads of the last version of RealTemp, it's obvious that users are interested in this subject. This new Target TJ spec needs to be investigated further and the Core 2 Duo B2 Stepping seems like the best choice for that.
Yea they must have a ton of ancient hardware lying around. Perhaps I should donate my E6600 and they can buy me a replacement :D It would be interesting to see if they can get it to run cooler than I can too.
EDIT: If you look at the presentation from August, it says:
"Approximate temperature in °C can be calculated by:
Tj = Tj_target - DTS value"
In the October presentation, this no longer appears on the slides. Also, the slide that contains the 45nm desktop Tj Targets used to just say Tj; although the new slide still just has Tj in the slide heading.
August
http://i176.photobucket.com/albums/w.../dts_pres1.png
October
http://i176.photobucket.com/albums/w.../dts_pres2.png
Intel seems to interchange their terms way too much. I really don't understand what this presentation was trying to prove. First Intel say Tj Target is Tj Max, then they are saying it isn't a specification at all and the values they gave are enough evidence to say that it can't be Tj Max. I wonder if Intel really know what any of these terms are. They obviously forgot that there is no (publicly released) B2 Q6600.
What about Xeon 3110?
95C, slide on post 2374Quote:
Originally Posted by WaterFlex
funny if you have a xeon 3110 you get a sensible tjmax...intel wont screw with cpu meant for business owners
rge
Thank you!
My 3110 is accurate at Tjmax +- 1 C°. :)Quote:
Originally Posted by rge
I tested it with a big overclock, using PROCHOT signal to understand where Tjmax is located in C° scale, using RealTemp to monitor it.
I noticed that same coincidence. The Xeon E3110 and the E8400 look like twins on paper with the only real difference being the box, the etching on the IHS and of course the price tag. Maybe I should head to EBay and find an E3110 to see how it compares when under the IR gun. I'm guessing that they would be exactly the same even though their TJ Targets are 100C for the E8400 and 95C for the E3110. Maybe after the August IDF, the lawyers got loose and had to craft a new term, "Target TJ", to cover their butts.Quote:
funny if you have a xeon 3110 you get a sensible tjmax...intel wont screw with cpu meant for business owners
Here are a couple of my favorite quotes from the October IDF:
"– It may not be possible to use software to identify exactly which
device is installed in the system"
"– Consequently, software may not be able to determine the
appropriate Tj for each part"
Translation:
Q: What is TjMax?
A: :shrug: :shrug: :shrug: :shrug: :shrug:
Yeah, would be funny if IR reads 95C at DTS=0 on E3110, or anything different than 5C.
I am once again confused with the gradient from core to Tcase (IR) with heatsink off... is it 1C, 2, 3, 4 or 5C at idle, underclocked. It is known 3C on a Northwood at stock idle with thermal paste for TIM1 and heatsink on...and removing heatsink doubles gradient by increasing resistance if using cpu with thermal paste as tim1.
But solder attach on E8400 has 10x less resistance than the thermal paste tim of northwood not to mention one would also think any increase in thermal resistance from removing the heatsink would be blunted b/c solder attach of IHS. Too many variables to guess. Mathematically still comes out to 1-2C using intels theoretical formula (heatsink on) but whether we would see that as 1-2C or 1-4C (plus/minus measurement error) with heatsink off (increased resistance)...who knows.
Regardless, using IR based tjmaxes accurate within a few C of gradient/measurement error are going to be a helluva lot more accurate than intels tj target plus or minus 20C offset, plus or minus 5-10C sensor error, plus or minus slope error.
about 8 hours of drilling holes in cpus and comparing die temps to tcase temps....curiosity was getting to me.
I borrowed an accurate surface temp thermocouple, has flat tip as opposed to wire one, and was reading almost exactly in line with IR gun, sometime .5C higher, sometimes 1C lower, mainly from different sensor sampling times.
First on pentium 4 since it has a soldered IHS. I measured with both IR gun and fluke temp probe which reads surface temps...and slowly brought up to shutdown temp....It shutdown at an average of ~76C Tcase (would ?throttle for few seconds and reduce temp 2-3C then cut off) I did this about 15x and mapped out a circle on the center of cpu that gave same temps consistently and same cutoff Tcase temps consistently (within +-1C). I then drilled a hole in the center, through half of the marked area, leaving other half for tcase measurement. When I got down to solder I switched from drill to dremel....saw small hole of mirror surface in couple spots...but a little aggressive with dremel and scratched core surface...but cpu worked fine.
Ran the temp up and could hold it under cutoff for minute or so with big fan (equilibration in seconds anyways) and running probe from die to tcase back and forth, probably tested 20 or more runs and hundred times...always 3-5C gradient, vast majority reads ~4C higher die temp than tcase.
Then ran it slowly up to cutoff temp 7X reading Tcase each time beside the hole, and then 7x more reading die temp with surface probe in the hole.
Die temp reaches avg. 80.7C, then throttles, drops temp few C for few seconds, then cuts off.
Tcase temp reaches ~76.3C then throttle, drops temp few C for few seconds, then cuts off, highest temp reached recorded.
Cpu shutdown die temps, highest recorded, measured with fluke temp probe
80.8, 80.1, 81.2, 80.5, 80.4, 80.9, 81.3
Shutdown Tcase temps (before and after drilling holes ~ same) measured with fluke temp probe.
76.5, 76.1, 76.7, 75.7, 75.6, 76.6, 77.1
Also using IR to measure Tcase and fluke probe to measure Tcase, tracks within half a degree celsius...but then using IR to measure Tcase and surface probe to measure die, die temp always 3-5C and avg 4C higher.
A couple of interesting things, as soon as power cuts off, Tcase =Tdie, ie as soon as die temp is no longer producing heat, equilibration is instantaneous.
Also, I stacked another IHS on top of IHS, and again only get 2C gradient...I think that is b/c die to IHS is closer to core heater than IHS to second IHS, and also going from small surface area to larger surface area incurs bigger gradient vs identical surface areas of IHS to IHS.
But I am now convinced on cpus with a solder attach, there is going to be a ~4C gradient from die to Tcase when heatsink is off. Hence need to add 4C to IR Tcase temps to get tjmax. So I am back to thinking E8400 tjmax is about right at 100C.
May post more this weekend if do some more playing.
I have not drilled my E8400 yet, that will be last test. After benching and failing to get 5hz 3x now, only 4.9ghz, even tried 1.9v yesterday...my E8400 now has degraded for 3rd time and needs 1.45v for 4 ghz (passes 10 linpack)...I would like to do same test on E8400 since it runs at slightly lower volts....but would be surprised if saw anything different than 3-4C at this point. But not going to drill it until I decide on getting E8600, q9650 or nehalem and wont decide that til nda is up and people post more nehalem results...as my E8400 is the only cpu in my house without a hole in it (other than wifes)
:up: Thumbs up rge for going way beyond the call of duty. :up:
I'm in total agreement that TjMax=100C is very reasonable for the 45nm E8x00 cpus and the core temp being about 5C higher than IR IHS surface temp measurements is also very reasonable.
I plan for RealTemp to continue using that number for most 45nm CPUs. For the original E6x00 - B2, I will be using 10C less than that or TjMax=90C regardless of Intel's recent IDF announcement. Using Intel's new Target TJ spec as TjMax just doesn't make any sense for most 65nm processors.
I would still like to get a Xeon E3110 for some testing just to see how it compares to an E8400. If I ever find one that is guaranteed to be E0 then I'll jump on it but the ads I've seen don't mention an sSpec number.
I'm suspicious that my assumption that a well air cooled Core 2 Duo should run about 5C hotter than ambient at low MHz and low voltage might be too conservative. Maybe our calibration method at low volts / low MHz should be based on 10C. :shrug:
With my Tuniq in the way, it's hard to get in for an accurate IR measurement and as you know, as soon as you remove the heatsink, temperatures shoot up in the blink of an eye.
Can you think of any way to get an IHS temp measurement or maybe a heatsink temp measurement near the IHS? If the heatsink is installed you might come up with a number which proves or disproves that 5C over ambient is reasonable.
It would be nice if Intel had a glossary with all their fancy terminology saying exactly what Tj Target is. But I suppose they'd need more than one definition, because to me it looks like they use the same term for more than one thing. There's no reason why Intel would lie about the numbers they gave us, but if it is possible to get temperatures being reported below ambient on air then Tj Target can't be (exclusively) Tj Max.Quote:
Originally Posted by unclewebb
But Intel gives several indications that it is, in both presentations. They had an updated slide on monitoring utilities showing the updated Tj Max and then said "65nm and Xeon processor information available today." That and the little formula they showed in the August presentation is evidence that Tj Target is Tj Max. I can only think that it is sometimes Tj Max and sometimes something else that Intel hasn't said.
unclewebb, if you get a xeon 3110, would be interesting to see IR reading.
IHS temp with thermocouple would be interesting to do...maybe I should dremel a groove in my E8400 when it comes time for its sacrifice, since I am already sure of die/tcase gradient w/solder. :D I might be able to position the surface thermocouple to do that, would obviate the need for calibrating a wire one, which i have no means to do.
Randomizer, I agree intel is likely telling the truth (just omitting actual offset numbers).
Intel states temp = tj target-DTS + sensor offset. That formula can be rearranged to
TEMP = (tj target + offset) - DTS
They said in slide, most (not all) DTS are set higher than tj target, and if 45nm have no significant offset or even 1-2C but 65nm have 10-20 offests that is consistent with that presentation. Looking at slide 7 graphs, if drawn to scale, it is easy to imagine a 10C or 20C offset in some cpus.
So for E8400, offset = near 0, so
TEMP = tj target + 0 - DTS or simply TEMP = tj -DTS
For E6600, offset = 20C, so
TEMP = tj target + 20C - DTS. So unclewebb is simply adding 20C (offset) to tj target to get accurate reading for E6600.
The above is exactly consistent with intels presentation...but would have been nice to be given offsets, though maybe they vary few C part to part in addition, hence would be messy.
Maybe testing early samples of core2duo required lower tj...then on release samples with improvements/different stepping they required large offsets and they never changed tj, just kept using offsets:shrug::shrug:
"...in most cases the DTS calibration point will be higher than the Tj Target values"
It's quite possible that the Xeon E3110 which has an Intel TJ Target = 95C, might still be TjMax = 100C, same as its twin, the E8400.
When the offset X isn't defined by Intel, the list of TJ Target values isn't very useful. They probably just got tired of being asked the same question all the time, "What is TjMax?" I know the feeling. :yepp: They threw us a bone but there's no meat on it.
The sad part is that this is going to continue into the next generation of Core i7. They may be adding a register that contains a Target TJ value which might be an improvement but that doesn't directly translate into a TjMax value so we'll still be guessing at what sort of offset we need to add to that number. At least users will have a new number to compare to each other when looking for golden chips.
Hm, is it possible that E5200 @ 3,875 (1,35V) GHz is running at only 38°C after few minuts of Orthos? I know 45nm parts are cooler but i never expected they are that much cooler (compared to E4300). Oh, btw, i have a sensor stuck on core1 yey. It seems sensor failure rate goes sky high with 45nm CPU's. I rarely heard that 65nm chip had a stuck sensor.
:p: