He wants to know if his CPU is running at -27 or 4 degrees C...
muahahahahahahahaha
Read the thread, nistomasx, use CoreTemp, and learn to love DTS.
He wants to know if his CPU is running at -27 or 4 degrees C...
muahahahahahahahaha
Read the thread, nistomasx, use CoreTemp, and learn to love DTS.
Core Temp .95 gives me a Tjunction of 100C for my e2160. Does this sound correct?
Nistomax: Here's a good example why I don't put too much faith in the CPU temperature reported by most motherboards.
13C is a great temperature but in a 22C environment with an air cooled processor it's impossible. SpeedFan reads this sensor and reports it as CPU but it's obviously meaningless.
For my E6400, when software guesses that TjMax=85C, I think the DTS is providing a pretty good approximation of what my absolute core temperature is from say 45C to 85C but I'm not convinced that the DTS is accurate at lower temperatures. It was designed and calibrated to be accurate at the throttling point but I have no data to prove how accurate it is at low temperatures like you're running.
Even if it's not accurate for reporting absolute temperatures, it is always accurate at reporting relative temperatures. If CoreTemp 0.95 reports that your Delta to Tjunction is 80C one day and then you do a few mods and it reports that your Delta to Tjunction is 85C the next day, your processor is definitely running 5C cooler than what it was running at before.
The DTS was designed to report how far you are away from TjMax and for that purpose, it's fully documented, calibrated and it's the best temperature information available for users.
e4300 revision l2 have a 85 or 100 tjunction?
Probably not. The new E2160 is identical to an E4300 but with half the cache disabled ( 1MB vs 2MB ). CoreTemp 0.95 assumes all revision L2 desktop processors like yours have a TjMax = 100C but they are all very likely TjMax = 85C. SpeedFan 4.32 assumes TjMax = 85C so use it if you want to see an absolute core temperature.Originally Posted by cowlickkid
That's just my guess and whether I'm right or wrong isn't important. Read this thread and set CoreTemp 0.95 to "Show Delta to Tjunction temp." That reads the sensor directly, tells you how much head room you have and then there's nothing to argue about.
I have read the thread and understand it, especially your well done explanation on page 8 Uncle. The reason why I was curious about the reported 100C tjunction was if there was some physical characteristic of the e2160 that would give 15C more headroom compared to other Core2 processors?
In theory a maximum Tjunction of 100C would give you 15C more headroom than a processor with TjMax of 85C.
There's no documentation from Intel to confirm that the TjMax for desktop processors is 100C or 85C or anything in between. When CoreTemp was updated from version 0.94 to 0.95 it decided to start guessing that all of the revision L2 Core 2 processors are TjMax=100C and the revision B2 are TjMax=85C. There's a pretty good chance that CoreTemp is wrong.
Other users here will argue that it might even be a completely different value. No one knows for sure so the only thing we can go by is "Delta to Tjunction" which is correct for all Core based processors.
Last edited by unclewebb; 07-13-2007 at 07:23 PM.
Greetings!In CoreTemp 0.95, 100ºC.
In CoreTemp 0.94, 85ºC.
When the E4300 arrived, CoreTemp 0.94 showed a too low temperature so the author bumped tjunction to 100ºC.
Funny thing is that TAT automatically adjusted to the new L2 core. And is probably the most reliable temperature reading program for C2Ds.
If THG did this right, the L2 stepping, with all throttling options enabled in BIOS, also throttles at 85ºC:
After 3 minutes 15 seconds, the B2 stepping began to reduce its speed due to overheating (87°C), protecting itself by throttling the clock speed.
By comparison, the L2 stepping held out a full 5 minutes before its internal heat sensor triggered the throttling feature.
impar: THG is usually pretty good but they didn't mention what software they're using to measure temperatures. Without knowing that and what assumptions that software made about TjMax, their results are meaningless.
You are right about what caused CoreTemp to change its assumption about TjMax from 85C to 100C. The graphs show the L2 having a lower idle temperature and the slope of the graph confirms that the L2 uses less watts and therefore produces less heat than the B2. The L2 E4300 also had a lower idle MHz when SpeedStep and C1E enabled, ( 1200 MHz vs 1600 MHz ) and because of their reduced idle wattage and heat output, absolute core temperatures with a good cooler were being displayed that were below the ambient temperature which is impossible.
The programmer of CoreTemp's solution was to add 15C to the maximum Tjunction which corrected this problem at low temperatures. I don't agree with that decision though. I think the real problem is a DTS that is not accurate at low temperatures and modifying the TjMax may correct the low end but results in absolute temperatures being misreported too high at full load.
With the voltage and MHz dropped down, my B2 E6400 can also report absolute temperatures below ambient and a good 10C below the temperature of the copper plate on the bottom of my heatsink, both of which are impossible. Using a 100C TjMax for my processor to try and cure this problem results in completely unbelievable reported core temperatures at or near TjMax.
Without any documentation from Intel saying what TjMax really is for the Desktop processors, all software calculating an absolute temperature based on an undocumented TjMax is only guessing.
TAT may have the Intel logo on it but it does not track the on chip DTS exactly and depending on the temperature or the day of the week, it does vary. It was never designed for the desktop processors and has never been updated since the Core 2 Duo desktop processors were introduced.
I originally posted this at the [H]ard forum but I think it's relevant and this procedure can be used to test how accurately programs that people take for granted actually track the DTS.
I use CrystalCPUID to read the on chip model specific register ( MSR ) that contains the raw DTS information. The 7 bits of temperature data are located in bits [22..16] of MSR 0x19C in all Core based processors.
Here's my E6400 ( 3600 MHz 1.504 volts ) at idle in a 22C room with the Tuniq Tower fan at its lowest speed of 1150 rpm.
When you enter 0x19C in the MSR Number box and click on RDMSR ( Read MSR ) you will get the value of the DTS. In this example bits [22..16] corresponds to 36 hexadecimal which is ( 3 X 16 + 6 ) = 54 in decimal. This means at idle I am 54C degrees away from TjMax which is the Intel documented highest safe operating temperature for a C2D cpu.
If RMClock is using the DTS and calculates the absolute core temperature to be 33C then it must be assuming that my TjMax = 33C + 54C = 87C. That's certainly possible but now let's check it again at full Orthos load.
At 3600 MHz and 1.480 volts it is happily running Orthos within 18C of TjMax. RMClock reports a core temperature of 63C so now it must be assuming that TjMax = 63C + 18C = 81C.
The maximum junction temperature of your processor ( TjMax ) is a fixed value, set at the factory and doesn't change yet RMClock is using two different values depending on whether the processor is hot or cold. That's not right. I also performed this test with TAT and the calculated TjMax could change from day to day which is also impossible.
Now you can run CoreTemp 0.95 or SpeedFan 4.32 and you will see that both of these programs track the on chip digital thermal sensors exactly. CoreTemp may be guessing wrong at TjMax but it can be used to report the DTS directly. When it is set like that, it reports the temperature data in processor register 0x19C exactly.
This is the only Intel documented core temperature information for a Core 2 Duo desktop processor.
Edit: On the main page of CrystalCPUID you can set it to read any of your cores. TAT is using different TjMax values at idle, at full load and even CPU 0 and CPU 1 are not consistent.
Last edited by unclewebb; 07-14-2007 at 02:18 PM.
...just though it deserved to be repeated...
heh heh heh, apologies for digging out this old thread but it's just an invaluable resource for Core temperature/DTS monitoring info
Before I start I should make it clear I understand that all Core2 desktop CPUs have no Tjunction value and as a result they should probably all be configured to read the DTS values however there is already a massive amount of info out there in regards to the Conroe Core 1066Mhz FSB Core2Duo and Kentsfield Core 1066Mhz FSB Core2Quads that have a "safe" CoreTemp load threshold of 65C and 75C respectively. Changing that perception, imho, would take more work than any benefit it may achieve.
As I'm sure you're all aware, the new 1333FSB processors are another CPU that seems to be having incorrect readout issues with the normal configuration of CoreTemp. I also have a sneaking suspicion that this applies to the E2140/E2160 CPUs as well.
This is all well and good as all who have followed this thread know you can just configure version CoreTemp v0.95 to report the DTS readings.
The problem comes with new users and what appears to be a lack of an easy to find thread which details the processors that are affected by this Tjunction issue and also a detailed method on how to configure CoreTemp to show the DTS.
I admit my understanding of actual CPUs affected by this is limited compared to many who post here, but I am assuming that:
E4300/E4400/E4500
E2140/E2160
E6x50 (1333FSB based CPUs)
Should all have their core temperature monitored by reading the DTS.
Another general assumption I'm working with is that the Core2 CPUs should be run no hotter than within 20C of the DTS 0C mark.
- This assumption is based on the first Conroe CPUs where initial testing seemed to show that staying under 65C (20C lower than the 85C nominated Tjuction) was the best threshold for a "safe" overclock.
I have also put together this image on how to configure CoreTemp v0.95 to show the DTS readouts.
This kind of information would make a handy sticky in the "Intel Info And Support" section for easy reference to new users of Core2Duo/Core2Quad.
I can start a thread if people here think it's worthwhile but I'd prefer to get some feedback on whether the CPUs listed above are the main ones affected by this issue.
There's also need to be a Mod to sticky it otherwise it's pointless.
Last edited by SLi_dog; 08-14-2007 at 09:49 PM.
Doing it the correct and Intel's way DOES REALLY matter !
Ever wonder how are those Intel CPU engineers measure Intel's own CPU in their uber leet lab ?
Warning, cpu pron pics inside, not advisable for minor !
Intel® Core™2 Extreme Quad-Core Processor and Intel® Core™2 Quad Processor Thermal and Mechanical Design Guidelines Download the PDF file.
For those who likes quick shortcut, just go to page 81 and beyond !
After you've read that and if you believe it, next time you will start chuckling & gigling back there when you hear these kinda comments :
"TAT cpu temp reading rocks ! I ignore others"
"Coretemp is the best and I believe it !"
"Temp diode reading is the most accurate one"
"The Tjunction should be xxx, not yyy .... "
..bla..bla..
For those non believers even after you've read it, c'mon, if this Intel's document can not be trusted, then what else ?
Or that program that shows the temp that you "want" to believe ?
Conclusion ? Software based for absolute CPU temp reading is NEVER ACCURATE, period !
Edit:Repost.
The general assumption that DTS=20 or 65C is a good number to shoot for when overclocking is too vague. 65C is an undocumented absolute temperature and people's definition of overclocking varies. My E6400 runs fine at 80C (DTS=5) when overclocked to 3200 MHz but 60C (DTS=25) is a good upper limit when I'm pushing it to 3600 MHz and a little beyond, God willing.SLi_dog: Another general assumption I'm working with is that the Core2 CPUs should be run no hotter than within 20C of the DTS 0C mark.
That's my conclusion and it applies to all Core processors. There's a reason why Intel engineers outline such an elaborate process to come up with an accurate Tcase temperature.Software based for absolute CPU temp reading is NEVER ACCURATE, period !
The new revision G0 processors, especially the dual cores, use significantly less watts at idle than the previous B2 processors ( 8W vs 22W ) when C1E is enabled. That's even less than the 12 watts that the L2 processors ( E4x00 ) are rated at. This is resulting in some impossible looking idle temps that are well below ambient when air cooled. For me, it's just more proof at how inaccurate the DTS is at reporting low idle temps which it was not designed for. I believe the DTS may start losing accuracy below 50C so even load temps for well cooled G0 dual core processors at default MHz and voltage may not be accurate.
Using the DTS to report absolute core temperatures the way SpeedFan and CoreTemp do is not documented by Intel and is just plain wrong. No matter what TjMax is chosen, I don't believe you can get 100% accurate core temperatures this way across the full range of temperatures that a Core processor can operate at.
The DTS was designed and calibrated to signal and control the thermal throttling and shut down points of an Intel Core processor and for that purpose, it works excellent. Using CoreTemp 0.95 as shown above to keep track of temperatures relative to the throttling point is the only thing users should be keeping track of and using the DTS for.
Last edited by unclewebb; 08-15-2007 at 10:24 AM.
It may appear to be more vague that it really is. By definition, running your CPU no closer than 20C from the DTS 0C point means exactly that. You'd have to factor in maximum CPU load and maximum ambient operating temperatures into that threshold. eg, don't go setting the 20C DTS rule as an idle temp at 6am in the middle of winterThe general assumption that DTS=20 or 65C is a good number to shoot for when overclocking is too vague. 65C is an undocumented absolute temperature and people's definition of overclocking varies. My E6400 runs fine at 80C (DTS=5) when overclocked to 3200 MHz but 60C (DTS=25) is a good upper limit when I'm pushing it to 3600 MHz and a little beyond, God willing.
I kinda threw it out there as a rough value for beginner users but it is well and truely open for discussion and I actually wouldn't apply it myself in the case of a Core2Quad. I guess the question then is, if not 20C, then what? Maybe 25C as you use?
Also, I personally wouldn't run a CPU closer than 20C to the 0C DTS point at 24/7 settings regardless of whether it was at 2.4Ghz or 3.4Ghz so I may have misunderstood what you're saying there.
Absolutely and that's fine for you, Bing, myself and everyone else who has followed this thread but I guess you're missing the point of my postThat's my conclusion and it applies to all Core processors. There's a reason why Intel engineers outline such an elaborate process to come up with an accurate Tcase temperature.. My point was that this information needs to be easily accessible to the average overclocker and it doesn't appear to be.
This seems to contradict your previous statement agreeing that software based absolute temperature are inaccurate. If they're inaccurate for absolute temperatures, I can't understand how they can be used to indicate that the CPU temps are lower than ambient?
Admittedly my understanding of thermodynamics is reasonably limited but I find it hard to believe that any amount of current could exist at a lower temperature than the air that's being used to cool it (Note: I understand about surface area and heat transfer)
At the risk of repeating myself, I guess you're missing the point of my post. My point was that this information should be easily accessible to the average overclocker. From the large amount of threads on this subject here and at other online OC forums, it currently doesn't seem to be.
From following this thread I assumed that there was enough know-how and experience here to put something together that could be of great use to the wider OC community.
Last edited by SLi_dog; 08-15-2007 at 08:35 PM.
Common Sense !
Agree, if its accurate, it will be every OC-er dream isn't it ?Absolutely and that's fine for you, Bing, myself and everyone else who has followed this thread but I guess you're missing the point of my post
My point was that this information needs to be easily accessible to the average overclocker and it doesn't appear to be.
But unfortunately the answer is "NO", you won't and can't get that info since Intel doesn't have it for them self !
1st thing pop out from the mind after reading my above statement is "Huh ? Why & How the heck I know that ?"
Ok, here are my explanations, its just basic electronic that every EE learned on their 1st year and "common sense".
1st, you have to understand that popular "tdiode" in that silicon die is basically a plain jane diode, and it is the very basic structure of silicon electronic.
A diode consist of "PN junction" (try wiki yourself, since it will be too long here) that has an interesting physical characteristic, it has a predictable and very linear behaviour response on it's temperature coefficient which is approx. 1.22 mV/deg F or 2.2 mV/deg C.
So whenever there is a changes in the temperature, we could track the changes (delta) temp quite accurate, hence it is used intensively to control the cooling parameter in Intel CPU mechanism, for example adjusting fan speed accodingly, or throttling up/down the PWM controller and etc. The word PECI come in mind !
Now you might ask how about the absolute temp reading ?
This is the weakest point, cause no diode in this world have a same temperature offset even they were produced in the same batch. Unless you could make that diode by assembling atom by atom at the precise location for all diodes.
So to make an accurate absolute reading, we must calibrate each diode in a controlled temperature room at high & low temp to get the offset temp for "EACH" diode.
If Intel want to give us an accurate temp reading on "EVERY TDIODE" in the CPU they sell, they must calibrate "EVERY TDIODES" that is spreaded in that CPU at silicon die level. Fyi, each CPU has more than one Tdiodes.
Layman term, they have to toast every cpu die and measure every tdiode in it at the temperature controlled room at cold and hot in order to get the offset of each tdiode and write/burn down that offset value into the CPU die.
Sounds complicated isn' it ?
Now, imagine you were Intel management, that always struggling to optimize your production cost at each CPU. Do you want to do that ?
Remember, Intel "officially" never endorse or encourage overclocking on their CPU.
Hope this helps.
Last edited by bing; 08-15-2007 at 10:14 PM.
It does, thanks. This is a great thread and is full of great and useful information and your post is no exception
In regards to the variations in the individual diodes used, I understand the nature of that but I had the impression that each DTS was calibrated on a per CPU basis already, possibly for that reason?
If the DTS read out indicates a CPU's approach to it's throttle point (which is defined by Intel themselves), what's would be the potential danger of giving a value of say 20C from 0C DTS as a rough guideline for Core2 CPUs? I think a statement like that would do much more good than harm. It would also be much better than what is currently being applied where the "actual temperature" value of 65C is used across the board regardless of whether people are "informed" about the flaws of certain applications with certain Core2 CPUs
Last edited by SLi_dog; 08-15-2007 at 11:46 PM.
Intel die is using MOS process, its just a type of silicon processing.In regards to the variations in the individual diodes used, I understand the nature of that but I had the impression that each DTS was calibrated on a per CPU basis already, possibly for that reason?
If the DTS read out indicates a CPU's approach to it's throttle point (which is defined by Intel themselves), what's would be the potential danger of giving a value of say 20C from 0C DTS as a rough guideline for Core2 CPUs? I think a statement like that would do much more good than harm. It would also be much better than what is currently being applied where the "actual temperature" value of 65C is used across the board regardless of whether people are "informed" about the flaws of certain applications with certain Core2 CPUs
If you watch closely "almost" all other electronic chip's datasheet that is using MOS process, has the "absolute" maximum operating temperature on the junction at least 100 C or even more.
Now, Intel's specification at their datasheet stated that the maximum TC or IHS temp at TDP 130 Watt is at 54.8 C, this figures quoted from QX6800 datasheet, imo, currently this is their hottest CPU that they released for "enthusiast" market since they're supposed the owners will OC them.
What strange is, they stated the max temp at the TC (IHS) temp instead of Tjunction temp as common industry standard. Dunno why, don't ask me.
But after some "quick & dirty" thermo dynamic calculation on the IHS and of course some safe "assumptions" included, it's like they're blessing the max tjunction at approx. 85C.
If you ever did DIY in electronic or experiment by using common diode as temp probe, and more than one of course, you will know that the offset deviations for diodes as I mentioned at my previous post rougly hovering about + or - 15 to 20 C. Voila !
So simple conclusion, the accuracy for any uncalibrated diode as a temp probe is about +/- 15 to 20 C.
In the worst case scenario, if they're off by even - 20C, meaning the cpu is actually hotter 20C more than the reported temp by the tdiode, still the cpu is in the safety margin/limit before the thermal/throttling mechanism kicks in.
Another quote from Intel CPU datasheet :
I can only speculate that Intel just use "cheap & quick" testing and verification method to determine that "throttling temp" since they're still at the safety margin.The temperature at which Thermal Monitor activates the thermal control circuit is not user configurable and is not software visible
Now other view angle, that crappy Intel stock HSF thermal resistance at full speed fan is 0.2 C/W. (this is the official number from their datasheet too)
OT, I hate that these days, popular HSF makers don't like to mention this very important specification (C/W) in their product anymore like in the old day.
Now the calculation as usual and using 130 Watt power dissipation :
IHS Temp = (Ambient Temp) + ( (Heatsink C/W) X (Power Dissipation) )
hence
IHS Temp = (Ambient Temp) + ( 0.2 C/W X 130 Watts) = Ambient Temp + 26 C
So "on paper" the max. ambient temperature for this QX6800 beast using stock HSF at 130 Watt full load is at 28.8 C
Of course we all know this is strictly "on paper", real life those limits are much higher and more relax since they just want to play it safe at the "official" paper.
Now, if the CPU is not Extreme version which has lower TDP, I'm quite confident that they (Intel) is also making a safe and calculated assumption like this :
Ignore or don't care at the tdiode values, with a cpu running "at stock speed/not OCed", with stock Intel HSF, and at full load in the room temp as high as 30 C, it is very safe to assume that the CPU is still on safe temp limit.
Don't you agree ?
This is how I see this overall issue.
Last edited by bing; 08-16-2007 at 02:25 AM.
Just to through another spanner in the works, i use asus PC Probe (good for voltages, picks up droop well) NVMonitor and coretemp. Both asus probe and NvMonitor read exactly the same, coretemp reads 2 degrees lower, but shows both cores. I always assume the worst, so i just take into account these temperatures, but assume the highest is correct, then i know i should be safe.
A +/- 20C error margin is damn scary. That would be a worse case senario though yeah? I'd hope that Intel used used better diodes than thatIf you ever did DIY in electronic or experiment by using common diode as temp probe, and more than one of course, you will know that the offset deviations for diodes as I mentioned at my previous post rougly hovering about + or - 15 to 20 C. Voila !
So simple conclusion, the accuracy for any uncalibrated diode as a temp probe is about +/- 15 to 20 C.
In the worst case scenario, if they're off by even - 20C, meaning the cpu is actually hotter 20C more than the reported temp by the tdiode, still the cpu is in the safety margin/limit before the thermal/throttling mechanism kicks in.
That said, the accuracy of the diode is not something we as end users can control and if it was misreading, it would affect the CPU as it approached the throttle point regardless of whether it was overclocked or not so it kinda a mute point to me
hmm interesting.Now other view angle, that crappy Intel stock HSF thermal resistance at full speed fan is 0.2 C/W. (this is the official number from their datasheet too)
OT, I hate that these days, popular HSF makers don't like to mention this very important specification (C/W) in their product anymore like in the old day.
Now the calculation as usual and using 130 Watt power dissipation :
IHS Temp = (Ambient Temp) + ( (Heatsink C/W) X (Power Dissipation) )
hence
IHS Temp = (Ambient Temp) + ( 0.2 C/W X 130 Watts) = Ambient Temp + 26 C
So "on paper" the max. ambient temperature for this QX6800 beast using stock HSF at 130 Watt full load is at 28.8 C
Of course we all know this is strictly "on paper", real life those limits are much higher and more relax since they just want to play it safe at the "official" paper.
I do agree that Intel likely aren't that concerned about whether the diode is that accurate because they've built in a fair amount of headroom.I'm quite confident that they (Intel) is also making a safe and calculated assumption like this :
Ignore or don't care at the tdiode values, with a cpu running "at stock speed/not OCed", with stock Intel HSF, and at full load in the room temp as high as 30 C, it is very safe to assume that the CPU is still on safe temp limit.
Don't you agree ?
This is how I see this overall issue.
However, if you replace the stock intel HSF with a good quality one and reduce the vcore to only what the CPU needs, you may be able to keep within or below this headroom even when overclocked.
- Example 1: A Q6600 at 2.4Ghz, on the stock Intel HSF, in a poorly ventilated case, with auto set vcore (usually around 1.35v) might have max load temps of 20C from the DTS = 0C point.
- Example 2: The same Q6600 at 3Ghz, on a Tuniq Tower, in a well ventilated case, with 1.21vcore might also have max load temps of 20C from the DTS = 0C point.
I don't see how one is worse than the other? I'm actually more inclined to believe that the second example is better for the CPU as it uses less voltage which reduces electron migration.
Last edited by SLi_dog; 08-16-2007 at 05:09 AM.
Actually, with the precision level at 65nm technology that Intel has, I believe they can narrow down that margin, by how much, no body knows except Intel. Or maybe other readers that is Silicon Wafer Processing Engineer want to jump in to shed some light here !A +/- 20C error margin is damn scary. That would be a worse case senario though yeah? I'd hope that Intel used used better diodes than that
That said, the accuracy of the diode is not something we as end users can control and if it was misreading, it would affect the CPU as it approached the throttle point regardless of whether it was overclocked or not so it kinda a mute point to me
Well, I've done in the past on Pentium D, the throttling point if I'm not mistaken (its too long ago) was about 90 - 95 C !
Did it by yanked out the stock HSF fan, and holding it right above the HSF with one hand and other hand ready on the power switch for emergency shutdown. And then run the proggy to load the CPU and ThrottleWatch for observing if throttling started, and marked down the temp when it started to throttle.
While running at max load, I sort of waived the fan farther and closer to the HSF while watching the CPU temp raised until it started to throttle. That was how I figured that throttling temp for my cpu.
If you feel gutty, you should try it yourself someday !
I believe that headroom is much-much higher than we thought, especially after with what I've experienced on that waiving fan game. he..he..
Why not do some simple math to see which one is better !
Fyi, nowdays most mobos do cheat when on Auto vcore, ok, not cheating, but they deliberately mark up the vcore for some headroom like compensating weak PSU factor, cheats on benchmark like Asus which is known always does OC on the Clock Gen chip with abit higher on stock speed and etc.
Lets take latest Q6600 G0 for example, average VID is about 1.2850 Volt, (you might check this as well HERE)
Now, before we start calculating, assuming all factors are ruled out like it has ideal PSU, ideal PWM with nice flowing VCore juide, ideal heatsink mount.
Fortunately, you've pick good HSFs both with thermal spec according to the manufacturer which are :
Data :
Q6600 Q0 Intel's TDP = 95 Watt
VID = 1.3 Volt
Stock Intel HSF = 0.2 C/R at highest fan speed
Tuniq Tower 120 = 0.12 C/W at 2000 RPM stock fan
Lets the math begin with this formula :
Power Dissipation (PD) = TDP x (OCSpeed / StockSpeed) X ( Square(VCore) / Square(VID) )
Example 1 :
PD = 65 Watt X (2.4 Ghz / 2.4 Ghz) X (Square(1.35 Volt) / Square(1.3 Volt) ) =
PD = 65 Watt X 1 X (1.8225 Volt / 1.69 Volt) = 70.096 Watt
Using Stock Intel HSF at 0.2 C/W
IHS Temp = Ambient + (0.2 C/W X 70.096 Watt) = Ambient + 14 C
Example 2:
PD = 65 Watt X (3 Ghz / 2.4 Ghz) X (Square(1.21 Volt) / Square(1.3 Volt))
PD = 65 Watt X 1.25 X (1.4641 / 1.69) = 70.39 Watt
Using Tuniq Tower 120 at 2000 RPM = 0.12 C/W
IHS Temp = Ambient + (0.12 C/W X 70.39 Watt) = Ambient + 8.4 C
Normally I would make the TDP a bit higher by adding more 10% or 20% to be more realistic.
So congratz, you're right, the example 2 with higher clock and also cooler temp !
Last edited by bing; 08-16-2007 at 08:47 AM.
I guess i will just add to this thread, instead of making another.
My question (at end) stems from ? contradictory statements in two intel spec sheets vs simply variance of measurement error.
first - has some interesting info including temp gradients
http://documents.irevues.inist.fr/bi...79/1/TMI23.pdf
here intel says
"The DTS also reduces the other temperature readings
errors, which are not shown in this paper. The DTS is
calibrated at manufacturing conditions and the reference
point is set to this test temperature. Functionality,
electrical specifications and reliability commitments are
guaranteed at maximum Tj as measured by the DTS. Any
test inaccuracy or parameters variance are already
accounted for in the DTS set point."
So sounds like I should be able to let the DTS go as low as I wish and be within specs, irrespective of actual temps, assuming voltage is within specs, and I can be stable.
In another spec sheet (previously quoted on here), it says Tcase max is 72C. When I gun the back of my cpu with my laserpro or use my wifes accurate touch probe and get 72C, the DTS by coretemp reads 18C (interestingly my cpu Tcase sensor says 71C so not bad, intel under one of its graphs mentions Tcase diode for 50-80C range, though with sample of one mine may just be "accurate" by chance).
Currently I am at 3.83 (E6850 on h20) with 1.4375 in bios, 1.41 measured on water with tcase load 58C (orhthos load). If I go to 3.94 at ~1.47 measured I get Tcase temps of ~72C on TAT (not orthos) full load. DTS reads 16-18.
I am probably going to stay at 3.83 anyway. But question is if I run at 3.94 and if my Tcase temps are running near max, am I slowly cooking my processor, or since my DTS is around 16-18 I am within specs?
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