Accuracy of thermister

[Compellor]

I'm just curious to know how accurate this thing is, and what is considered a safe temperature for an overclocked Duron CPU? I read somewhere that said the CPU core could be as much as 10 degrees (or more) hotter than what the reading of the thermister shows. I'm currently using a Vantec socket A heatsink/fan (using silicone thermal compound) and am getting a reading of 46C at idle and 47C - 48C at full load. My case temp is usually around 31C -- give or take a few degrees depending what time of day or night it is. My case has one intake and one exhaust fan. My system specs are listed in my signature below.

 

[Mikewarrior2]

Which bios are you running?

If you are using one of the newer Abit kt7 bios'(the one's that auto add the compensation to help alleviate thermistor inaccuracies), then your temps are fairly close to what they "should" be.

Your cpu should be putting about 40W of heat, and the vantec heatsink is probably around .45-.5c/w, you should be at least 18-20C warmer than ambient(that would be what core temp should be with your cooling setup).

With the older bios', they didn't compensate for thermistor's showing lower temps(for example, i played around wtih a Soyo7vca(a thermistor based p3 mb) and a cusl2(intenral diode readings), and the difference was around 12-15C). So with the older bios', people would be getting 31C ambient, and 34C cpu, which at full load is not possible on any duron with conventional air cooling.


Mike

 

[jinsonxu]

I'm worse off than you, getting 50-51 degrees C at 900Mhz and 1.55volts.

 

[Compellor]

Thanks for replying Mike. The motherboard came shipped with the latest UL bios.

Question: Would it be worth it for me to buy a better HSF to get better cooling for my Duron, or am I ok with my current setup? (I don't plan to overclock much more) I keep reading on this forum where people using Alpha's and Global Win's are reporting that their chips are running anywhere from 28C to 35C idle. But, they also say that their ambient temps are at or just a little below that. Is this possible?

 

[Mikewarrior2]

No, 30C on a O/C Socket A cpu is not possible unless your ambient is like 10C. Even with an Alpha/Globalwin.

With proper cpu core temp measurement, you'd be looking at a 1ghz Duron at 1.8 volts running about 24C over ambient temp. You'll see lots of people reporting a durons/t-birds at 950+ running at 35C full load, and 31C idle. That again is false, because idle to full load temps with p3 internal diode measurements are something around 10-12C difference.

This is a problem with the thermistor's not really showing the range of movement of cpu temps because of its placement. Unfortunately, AMD chips don't use an internal diode to report cpu temps.

Now, if you were to get an Alpha/Globalwin, you'd probably see a significant temp drop, probably into the lower 40's, but i wouldn't expect anything in the low 30C range.


Mike