Varying Temp. Readouts

[wviperw]

For my Abit KT7, there is tempurature readouts. I can look at the temp of the cpu and the case. In the BIOS it will say one temp, in SiSoft Sandra, it will say another temp, and in the VIA Hardware Monitor, it will say another temp. Like right now, VIAHM says it is 40/33 C (cpu/case). And in SiSoft Sandra it says, 53/26 C. If I would resart and go into the BIOS right away, it would say another tempurature.

Now, I read that SiSoft compensates the temp, because they expect the thermistor not to be touching the CPU. But I am pretty sure my thermistor does touch. And I can see the BIOS being a little different since it is running off the CMOS chip, but if I restart and get into the BIOS right away, then the CPU shouldn't have lost that much heat.

So which one should I trust? It seems like VIA HM, and SiSoft are always reading out the same temps, or slight variations of the ones that I gave you. Even after I play Q3A for awhile.

 

[Mikewarrior2]

you can't trust any of them.

Even if a thermistor is touching the back of the cpu, it means nothing. Chips change temperatures in very short periods of time. The time it takes to reset will drop the temp significantly.

With flip-chip cpus(durons and t-birds are manufactured as flipchips), the hottest part of the cpu is touching the heatsink. On the backside where the thermistor is, you are either touching substrate or a resistor.

Just you telling us that the temp doesn't vary much means the thermistor really isn't measuring the changes in the cpu core temp properly, even if it is touching the back of the cpu.

This ends up being a duron/t-bird problem because they lack an imbedded internal diode for measuring temps. VIA mb's are reduced to using a thermistor underneat the socket to measure cpu temp(why they do this on p3s, which have internal diodes, is anyone's guess). You can pretty much discount any result/reading you get from the thermistor, because it is inaccurate.


Mike