P4's temp probe accuracy?...

[touser]

hi all i was just wondering how accurate the p4's built in temp sensor is? because i just got a digi doc and at full load mbprobe reports it at being 44c, and the digi doc (who's sensor is touching the side of the cpu) is reporting only 28.6c!any help or comments are greatly appreciated :)

[ol' man]

PIV's don't have a internal thermal probe?

[touser]

i thought they had one dont they?

[Yodums]

I think they do but you have to attach it yourself..

I hope your not looking at the Motherboard temperature.

[touser]

nope it isnt the motherboard temperature :) i am looking at the cpu temp on MBProbe

[Yodums]

Thats really odd...
That just can't be right though.. That's a 15 Degree Difference.

[theflyingrat]

The Pentium 4 temp probe is internal - no installation. And accurate, AFAIK. This is how P4s throttle themselves - the onboard probe senses excessive heat and throttles itself with little/no input from the motherboard.

If you're getting too low of temp sensors from a digidoc, it may be because the sensor isn't touching the die (as Intel's internal thermistor is). It's only touching the metal cap over the die, in fact. I'd imagine this could distort the results quite a bit!

[touser]

Originally posted by theflyingrat
The Pentium 4 temp probe is internal - no installation. And accurate, AFAIK. This is how P4s throttle themselves - the onboard probe senses excessive heat and throttles itself with little/no input from the motherboard.

If you're getting too low of temp sensors from a digidoc, it may be because the sensor isn't touching the die (as Intel's internal thermistor is). It's only touching the metal cap over the die, in fact. I'd imagine this could distort the results quite a bit!
thank you theflyingrat that is the exact info i was looking for!, so i should go by what the MBProbe says over the digi doc. one question though what does AFAIK stand for?

[theflyingrat]

As Far As I Know....

It's dumb, yes, but it beats typing it out every time! :p

[Yodums]

I never knew P4 sensors was like that lol!

[touser]

ok i have gone over this time after time in my head and i cannot see how MBProbe is right! i have guys with t-birds aircooling overclocked 300mhz with lower temps then motherboard probe and MBM5 are reporting! i just don't see how it is possible for them to be lower then me on a hotter chip aircooled and i am watercooling..i think i am going to stick with my digi doc reportings of 25.4c idle it just seams more feasible then 40c idle!

[theflyingrat]

What kind of heat sink and fan do you have? If it's not a really large, heavy duty one, that may be the cause.

Your motherboard monitor of 40C is almost 100% favorable compared to your DigiDoc. Like I said, the thermal probe is integrated into the CPU die. There is no way to get more accurate than this. They've been doing it that way at Intel for years, and have really gotten very good at it.

The guys with Athlons OCed with Air cooling? That's probably a result of wildly pessimistic thermistors. You see, AMDs do not have built in thermal probes. Therefore, they have to rely on the motherboard manufacturer's crappy motherboard-mounted thermistor UNDER the CPU die. My brother has a DFI like this. It reads his peak temps at a mere 36C. This for a 1.0 GHz Thunderbird OCed to 1400+ with air-cooling at 1.85v. His last motherboard, an A7V133, reported the same CPU/cooler/voltage at a scorching 55C.

Now, if you were to swap your CPU into another P4 motherboard, chances are it would read almost exactly the same as your current one does. This is part of where the extra cost of buying Intel components is. Using high-quality parts inside the CPU to guarantee longevity and reliability.

[touser]

thank you theflyingrat, but the reason i cannot believe those temps is because i am not using are cooling! i am watercooling with a dangerden mazep4, eheim 317gph pump and dangerden cube radiator with 2 120mm fans on it! and i am absolutely positive that the block is seated correctly, i took out the whole motherboard and seated it to make sure it was seated perfectly.i am also using thermal compound between the block and the cpu..now my friend has the exact same setup but with an even smaller pump with 0 fans on his radiator but a p4 1.5 and his idle is only 29-30c! according to the same MBProbe program..

[theflyingrat]

Damn! That's quite the setup......hmm....did you check the temp monitor in your BIOS? That's ultimately the one you should go by; it's the one that will always read directly from your CPU. You're right....it should be lower with a turbo water machine of death like that, though.