Hi Rudolf, I calculated the time constant based on the temperature curve of "CPU temp". It is about 20 seconds. In my opinion, the time constant of the silicon chip is about 10 milliseconds. Does this suggest that the "CPU temp" is not the temperature of the thermal diode inside the Pentium 4 CPU? Oh, I just thought of one possible reason for this. Perhaps the current or the voltage drop of thermal diode is not changing so fast as the temperature change of the silicon area around it. So the temperature readings from the diode will lag. If this is true, this could explain why the readings from the thermal diode is not changing as rapidly as the temperature of the silicon area around it. But this explanation contradicts with the purpose of the thermal diode. If the readings from the thermal diode cannot catch up with the rapid temperature change, the thermal diode is not so useful. I am confused here. I still think the "CPU temp" should be the readings from the thermal diode inside the Pentium 4 CPU chip. But the fact that this "CPU temp" is changing slowly in seconds and it could not reach a high temperature makes me doubt it. Any suggestions are very appreciated! Thanks, Yongkui On 10/22/06, Yongkui Han <hanyongkui99 at gmail.com> wrote: > > Hi Rudolf, > > Thanks so much for your reply. > > I downloaded the CPU burn program, and run it to see how high the CPU temp > can reach. > > I run the CPU burn program for 10 minutes = 600 seconds. The temperature > curve for the CPU burn program is attached for your reference. The highest > temperature reached is 53C. I also drew the temperature curve for the 900 > seconds before running cpuburn, and for the 300 seconds after cpuburn > program exited. > > In the attachments, the file cpuburn.pdf is the complete temperature curve > for nearly 1800 seconds. The file cpuburn.100s.pdf is for the 100 > seconds time interval of [850, 950] only. > > The CPU temp is increased 4C (from 39C to 43C) during the first 8 seconds > when cpuburn program starts running. But it takes about 300 seconds for the > CPU temp to reach 53C. Does the CPU temp grow fast or slowly? > > Based on the temperature curve, which one do you think the CPU temp is > for? The thermal diode inside the CPU chip, or just a thermistor? > > Thanks! > > Regards, > Yongkui > > > On 10/22/06, Rudolf Marek <r.marek at assembler.cz> wrote: > > > > Hi Yongkui, > > > > > Thanks very much for your help. > > > > Well always good to hear it. Unfortunately I have not so much free time > > recently > > for this kind of lm-sensors support stuff. > > > > > The pin numbers for the thermal diode in the Pentium 4 CPU are H38 and > > > E39. I think the PIN 9 and 10 of ADM1025A chip are connected to the > > PIN > > > H38 and E39 of the Pentium 4 CPU. So the temperature output "CPU Temp" > > > > > from lm-sensors should be the temprature reading of this thermal > > diode. > > > > Good. > > > > > The datasheet of my Pentium 4 CPU is here: > > > http://www.intel.com/design/pentium4/datashts/249198.htm > > > ftp://download.intel.com/design/Pentium4/datashts/24919805.pdf > > > > > > > > > A picture for my CPU chip and the ADM1025A chip is attached. You can > > see > > > in the picture that the ADM1025A chip sits close to the Pentium 4 CPU > > > chip (the top-right location). > > > > It should be so - the analog lines are as shortest as possible. > > > > > The followings are some observations from my experiments with > > lm-sensors: > > > ----------------------------------- > > > The operating system is idle: CPU=35C, M/B=34C. > > > I run many CPU-intensive programs to see how high the CPU temperature > > > can reach. > > > The highest temperature I observed are: CPU=55C, M/B=47C > > > The largest temperature difference between CPU and M/B is 8C. > > > It takes about 8 minutes for the CPU temp to reach 55C, and then stay > > at > > > 55C. This means it reached its steady state temperature. > > > > Hmm this indicates perhaps the thermistor instead of the diode. It takes > > too > > long. The core temperature should grow very very fast. But if the pins > > are > > connected to the socket it must be diode. (and it seems that the chip is > > for > > diode only) > > > > > I expect the CPU temperature could reach 80C or 90C for some > > > CPU-intensive programs. But unfortunatly, 55C is the highest > > temperature > > > I observed so far. 55C is not so high in my opinion, why the CPU > > > temperature cannot reach 80C or 90C? The critical temperature for the > > > Pentium 4 CPU chip to shut down is 135C. > > > > Yes true. > > > > > Now I am wondering where this thermal diode is located inside the > > > Pentium 4 CPU. Is this thermal diode located near the Integer Register > > > unit, or near the Floating-point Multiplication unit, or near the > > Level > > > 2 Cache unit? You know, there is a large temperature difference > > between > > > two different locations on the CPU chip. > > > > Well this is not known. If some parts get too hot the CPU might > > throttle a bit > > to cool down. Maybe you could try the "cpuburn" software. > > http://packages.debian.org/unstable/misc/cpuburn.html > > (for debian) > > > > > Do you have any hints about the thermal diode location in the Pentium > > 4 > > > CPU chip? > > > > No but you may take a look to: Intel(r) 64 and IA-32 Architectures > > Software > > Developer's Manual, Volume 3A: System Programming Guide describes the > > operating-system support environment of an IA-32 and Intel(r) 64 > > architectures, > > including: memory management, protection, task management, interrupt and > > exception handling, multi-processor support, and thermal and power > > management > > features. > > > > There are some notes and stuff about the thermal monitor (the digital > > sensor > > have core/core2 cpus so perhaps not yours) > > > > http://www.intel.com/design/pentium4/manuals/index_new.htm > > > > All in all there is more then one temperature sensor, sometimes there is > > digital > > temperature sensor, and even the diode is locate on other place... > > > > > > You may check the "IA32_THERM_STATUS MSR" via MSR reads (/dev/msr/...) > > > > http://www.google.com/codesearch?q=+rdmsr.c+show:EynqVEYBclg:kdySSoK4L6Y:chKAG6mOivc&sa=N&cd=1&ct=rc&cs_p=http://www.stillhq.com/extracted/x86info-wx.tgz&cs_f=x86info-wx/x86info-1.11/rdmsr.c#a0 > > > > To sum it up. You need some cpuburn to burn the cpu. Then the temp > > should grow > > quickly. Using the MSR you may check if the CPU defend itself when too > > hot. > > > > I hope it will help you during your experiments. If you burn the CPU to > > dead ;), > > buy Core 2 CPU it has the embedded temperature sensor (and I wrote the > > driver > > recently) > > > > Regards > > Rudolf > > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.lm-sensors.org/pipermail/lm-sensors/attachments/20061023/a889892e/attachment.html
