Accuracy of mobo sensors

[JimmyBoy]

ive seen a lot of comments on here about people getting strange temps from their systems, put down to inaccurate sensors.

i was wondering with my setup (see sig) how accurate the sensor in this board is, im also running the asus probe software that came with it the reason i ask is i finally got the system stable at 10x240 as i was being to much of a sissy with the v core (now at 1.6) i intend to push higher, but am currently using the stock amd h/s (the lack of noise but good temps have pushed back me gettin a new one)

thanx guys n girls

[LeeumH]

They will never give a truly accurate read of temperatures, you're best buying a Matrix Orbital display with sensors accurate to 0.1 of a degree c, pricey like. If that's a little our your budget go for a little LCD and probe unit, they are accurate and come in some funky colours, what more d'ya want? WCS is the cheapest place i've found so far. Simply thermal tape the probe underneath the CPU and trace the small wire/s for it through the pins.
If you're not planning on spending money check your motherboard up and read the improvments on the latest BIOS', I flashed my NF7-S V2 today to fix my 20 degree's c over reading probe, turned it off when it saved my BIOS settings, oh dear. Looks like i'm on a mates P3 866 for christmas :|

[StormPC]

Yeah, and the problem is not the sensor necessarily. BIOS programming, integrating method and sensor placement also affect the reading. Accuracy is not very important. It's relative temps that you are interested in most. If your system is TRULY stable then it's not too hot.

[JimmyBoy]

ok guys, thanx 4 the replies and the useful info, i checked the asus site and on the bios rev list none of the 'fixed' list said anything about temp reading accuracy fixes, so it could be fine, current read at the mo while sitting idle 4 a while is 36 - 37c while bentchmarking it was around the 50 mark with the v core at 1.6 is that a very believable temp?, im happy with it just but id be really pissed off if it was acturally 56 - 57 idle...

[StormPC]

It's probably pretty close. Those temps are fine. Winnies run very cool, even with the 400MHz overclock you have (I run mine at 2480MHz 24/7). My MSI K8N Neo2 reports the temps higher or lower than actual depending on the BIOS I'm using. I know my system is stable even at much higher clocks (I've had it running prime95 for hours at 2600MHz+) so I don't care much what the motherboard BIOS says. I've probed it just to make sure however.

[JimmyBoy]

excellent, thanx a lot storm merry christmas

[SilentDeath]

Nope,they aint accurate atall. I would guess that the acctuall sensor and electronicsmay be accurate to +-3c.

Then I would add, look at the positioning of it. BELOW the cpu. Any heat has to travel through the cpu package to get to the sensor. The package has a fairly high thermal resistance = not all of the heat goes through = you get a much lower reading.

THEN when installing the cpu, how many of you put paste on the sensor,and bend it upwards to get better contact?nope, I dont either.

THERE is however, a simpler way. If you can solder small simple circuits, then its also almost free. www.maxim-ic.com look at MAX6657. You should be able to get free samples too - I did.
This then gets a measurement from a sensor internal to the cpu, which needs no calibrating, and is in perfect place for temp measurement. Theres almost no thermal resistance and so very sudden changes in temp are noticable instantly.

I b0rked all my samples, however I may try again, Ill post in the electronics forum, if anyones interested in following this.