Hi Ulf, The accuracy of sensors deteriorate more when far away from TjMax, a spec say the temperature error is about +-10C at 50C. So, as you said, the value is more reasonable after the cup load increased. Thanks Huaxu >-----Original Message----- >From: Ulf Granlund [mailto:galsjo@xxxxxxxxxxx] >Sent: Sunday, June 27, 2010 4:46 AM >To: khali@xxxxxxxxxxxx >Cc: lm-sensors@xxxxxxxxxxxxxx; Wan, Huaxu >Subject: RE: Too low temp readings on overclocked >Intel Atom CPU > > >Hi Jean, >I guess you are right about most of this. Clearly, the sensors >are very unreliable at low temperatures.If I leave the >computer switched off for a few hours in an ambient temp of 23 >C, and then turn it on,the senors show values in the order of >-5 C for the first few minutes before the machine is warmed >up,when reasonably, they should show about 23 C. And this is >when the CPU is running at standardspeed. So the error that >occurs from overclocking is relatively small compared to this >ca 30 C error. It possible that the sensors perform better at >higher temp, as you say, but how do I know that? I can stress >the machine and see that I get more reasonable values when the >CPU is working harder,and also the difference between >overclocked and standard speed is less pronounced at higher >working load, but there is no real way for me to tell when >they stop beeing completely wrong and start beeing right. >Hopefully they will at least fulfill the function of turning >the processor down before it burnsup, and apparently that is >the only useful function they have, it seems that they can not >really be used forreading the temperature. >However, I have one last question. Since the processor only >has two physical cores, butI get four readings, is there some >way to tell which values are the ones from the realcores? >Thanks for your advice,RegardsUlf >---------------------------------------- >> Date: Wed, 23 Jun 2010 09:53:51 +0200 >> From: khali@xxxxxxxxxxxx >> To: galsjo@xxxxxxxxxxx >> CC: lm-sensors@xxxxxxxxxxxxxx; huaxu.wan@xxxxxxxxx >> Subject: Re: Too low temp readings on >overclocked Intel Atom CPU >> >> Hi Ulf, >> >> Preliminary note: the mAtom 330 is a dual-core CPU, so you >really have >> 2 cores, not 4. I guess that each core has hyper-threading, which is >> why you see 4 CPU entries. But I suspect that there's only one sensor >> per core, so the coretemp driver should only display 2 values. I've >> sent a patch fixing this, but it didn't receive any comment: >> http://lists.lm-sensors.org/pipermail/lm-sensors/2010-May/028511.html >> >> About the Asrock software: it is possible that Asrock knows about the >> problem and silently compensate for it. You'd need to ask >them. But it >> is also possible that other CPU samples have working sensors when >> overclocked and only yours doesn't. Each CPU is unique when >> overclocking. The only way to know for sure would be to run >the Asrock >> software on your own system. >> >> Don't you have an external hardware monitoring chip on your board? It >> would probably be less influenced by overclocking, and would thus be >> more reliable for comparing the temperature with and without >> overclocking. >> >> Anyway, please note that the CPU temperature values reported by the >> coretemp driver are notoriously inaccurate as long as they are way >> below the critical limit. This is your case. So the bottom >line is that >> your CPU is very cool and you have no thermal issue at all. >> >> But beware, problems when overclocking aren't limited to a higher >> running temperatures. All kind of issues can happen, which you won't >> notice until things start failing mysteriously. And overclocking >> doesn't buy you much in practice anyway, as the limiting speed factor >> these days is more often the disk and memory speed than the >CPU speed. >> >> Jean >> >> On Tue, 22 Jun 2010 11:00:37 +0200, Ulf Granlund wrote: >>> >>> Hi Jean, thank you for your answer. >>> Some answers to your questions, as far as I can get them: >>> The CPU model is "Intel Atom CPU 330 @1.6 GHz" according to >system info in the BIOS. >>> CPU Voltage: From the manual or the Asrock home page, I >have not found any clear specification on exactlywhat >parameters the overclocking option alters. I found some >hardware review pages on the net stating thatwhen using this >option ( with the highest available frequency, 2100 MHz) the >CPU voltage is automaticallyset to 1.315 V. I have no idea >about how reliable this information is or where they got it >from. In the BIOS theoverclocking option is mentioned as "an >optimized set" of overclocking parameters, indicating that at >least morethan one parameter is affected. >>> When I load the CPU:s there is a clear raise in >temperature values both when I am overclocked and when running >atstandard speed, but for essentially the same CPU load >(watching a movie for 5 minutes) the temperatures are about 10 >to 15 °Clower in the overclocked state, which does not seem reasonable. >>> In the hardware reviews found on some net sites, it is >mentioned that there is a (Windows) systemmonitoring software >that is supplied with the system from Asrock. There is data >from this softwarepresented in the reviews, where temperature >readings are collected in both standard and overclocked >states, andfrom that software they get temperature readings >that are clearly higher when running overclocked, which seems >to bethe most reasonable result. To me this seems to show that >it is possible to get reliable temp readings also in the >overclockedstate. But then again that software is supplied by >Asrock, and I guess they have full control of all parameters. >>> Best Regards >>> Ulf >>> ---------------------------------------- >>>> Date: Mon, 21 Jun 2010 23:06:05 +0200 >>>> From: khali@xxxxxxxxxxxx >>>> To: galsjo@xxxxxxxxxxx >>>> CC: lm-sensors@xxxxxxxxxxxxxx; huaxu.wan@xxxxxxxxx >>>> Subject: Re: Too low temp readings on >overclocked Intel Atom CPU >>>> >>>> Hi Ulf, >>>> >>>> On Mon, 21 Jun 2010 12:19:50 +0200, Ulf Granlund wrote: >>>>> >>>>> Hello, >>>>> I am running an Asrock Ion computer under Ubuntu 10.4. It >has four Intel Atom CPU cores. In the Asrock BIOS thereis an >option to introduce overclocking. I have set the frequency to >1800 MHz insetad of the standard 1600 MHz.. >>>> >>>> By doing this, you are unsupported. If you decide to use >your hardware >>>> beyond its specification, you shouldn't be surprised if it fails. >>>> >>>> Please tell us the exact CPU model. >>>> >>>> Do you know if the overclocking alters only the frequency, >or also the >>>> CPU core voltage? >>>> >>>>> After having the computer switched on for several hours, >but the CPU:s mainly idle, the output from the sensors command >is as below,in a room where ambient temperature is about 22 C. >>>>> coretemp-isa-0000Adapter: ISA adapterCore 0: +4.0°C (crit >= +90.0°C) >>>>> coretemp-isa-0001Adapter: ISA adapterCore 1: +16.0°C >(crit = +90.0°C) >>>>> coretemp-isa-0002Adapter: ISA adapterCore 2: +3.0°C (crit >= +90.0°C) >>>>> coretemp-isa-0003Adapter: ISA adapterCore 3: +16.0°C >(crit = +90.0°C) >>>> >>>> This is horribly formatted. >>>> >>>>> Clearly these temperatures are way too low.However, if I >set the processor frequency to the standard 1600 MHz,I get: >>>>> coretemp-isa-0000Adapter: ISA adapterCore 0: +17.0°C >(crit = +90.0°C) >>>>> coretemp-isa-0001Adapter: ISA adapterCore 1: +25.0°C >(crit = +90.0°C) >>>>> coretemp-isa-0002Adapter: ISA adapterCore 2: +18.0°C >(crit = +90.0°C) >>>>> coretemp-isa-0003Adapter: ISA adapterCore 3: +25.0°C >(crit = +90.0°C) >>>>> Which at least seems far more reasonable. >>>> >>>> This is very interesting. Adding the coretemp driver >maintainer in Cc. >>>> >>>>> It seems that the more I overclock, the lower the >temperature readings get.Can somebody explain how to get >correct temp readings? It is of course more importantto me to >get correct readings in the overclocked situation than in the >standard situation... >>>>> The lm-sensors version used is 3.1.2 and the linux kernel >version is 2.6.32. >>>> >>>> First thing to check is: do the temperature values >increase or decrease >>>> when you load the CPUs? >>>> >>>> Then I guess you could give a try to the latest version of >the driver, >>>> as it received changes recently: >>>> http://khali.linux-fr.org/devel/misc/coretemp/ >>>> >>>> But anyway, odds are that the sensors are affected by >overclocking and >>>> nothing can be done, except: don't do it. >>>> >>>> -- >>>> Jean Delvare > >_________________________________________________________________ >Vårfina smileys till Messenger här! >http://springpack.msn.se _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
