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Trusting your CPU tempurature sensor.

  • Cooling
  • CPUs
  • Overclocking
Last response: in Overclocking
March 24, 2006 1:17:31 PM

Ok, I'm curious how much I should trust my CPU sensor. I have a 3800 X2 that isn't running as cool as it should be according to the numbers I've seen.

- I've only seen it below 40C when I was running it next to an open window (Out door temp around 40 F) and idle. That was with stock cooling.
- With stock cooling, I've seen it up to 57C, and regularly at 53-55C under load.
- With my Zalman 9500, I've seen it as low as 40 C Idle, and 46 C Load (Again, with cooler than normal ambient temps).
- With the Zalman, low is usually 42-43, and high 48-49.
- Overclocked to 2.5 Ghz with a 1.45V, Idles around 44C, Loads around 50C-51C (I've seen it at 53 if the room gets inordinately hot). 100% stable at this speed though.

Now, all of these temps are well beyond what I've seen posted online, and I'm wondering if either speedfan is using a different sensor than the one on the CPU, not reading all the temps correctly, or is just high (My Hard Drive is inaccurately detected as running 10-20C warmer than it actualy is) on this board.

Of course the other question, is if my CPU, under load, actualy is hitting 52C, is that a dangerous thing for it?

I'm using Speedfan for all my temps, but it can't read my board's voltages. Thunderprobe says they're all fairly normal, and occasionaly the CPU temp in Thunderprobe differs from Speedfan, usually lower by a degree or two (as well as slower to rise or fall).

Thanks for the help

More about : trusting cpu tempurature sensor

March 25, 2006 2:35:03 AM

Those temps really don't look that bad... Seems like these sensors can be off by quite a bit in my experience. If you're stable, I wouldn't worry about it.
March 25, 2006 9:33:28 AM

If 53 isn't much to be worried about, I'm happy, as that is the worst I've seen my system on the 2.5 Ghz OC (it was 77 F in the room)
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March 25, 2006 10:19:33 AM

dude ı got the same problem.

mine idle:42-43 load:51-52 at 2500 oc voltage: 1.52

but ı think it is a little bit related to mobo because temps with my old 9NDA3I were idle:34 load:42 same cpu and cooler but at default voltage and 2400 oc.

My present mobo gives 1.47 at default and 1.52 at +0.05 and temps are higher. ı don't know wheter the sensors are wrong or something wrong with my cooler. anyway ı don't have any instability issues and still those temps are at the safe zone
March 25, 2006 11:01:04 AM

So, maybe the EPOX boards are a bit liberal with the temp...

If I ever get a fan controler/temp monitor and hook it up to the CPU fan, I'll know for sure. However, I know the temp sesor fan in my PSU never gets too high, so I have to wonder if it's realy an issue.

Just don't wnat to fry the system.
March 25, 2006 11:07:00 AM

ı heard about the same thing about 9npa series in turkish forums. they are generally complaining about overvoltage and high temps but no one says it causes an instability and we knows that pc shuts down automotically when the cpu temp exceeds a certain level so nothing to woory about..
March 26, 2006 1:02:03 AM

Never fails. 8)

My 9500 feels cool to the touch with a 4400 under it. Heatpipes to where they come out of the base. Cool & Quiet OFF btw. I don't know how you are getting temps in the 40's with a CNPS 9500... :?

Did you use AS5 to mount it?
March 26, 2006 2:47:03 AM

Yes, I used AS5 to mount it, and it feels quite cool. I don't think it's correct.
March 26, 2006 6:30:12 AM

The three temps I have are...

According to speedfan

Temp 1: (Likely CPU) It seemed like it droped a degree today, perhaps the AS5 is begining to set, I had to reseat the HS earlier this week.
Temp 2: Lingers between 25-30, usually around 28. The BIOS has it listed as the chipset. I know this is cool for a chipset, probably warm for the internas case sensor.
Temp3: Mosfets? Runs between 75-85, usually either 78 or 83 (not sure why). I haven't found anything that runs that hot in the case, though I believe you mentioned that my mosfets were under the chipset HS.

Temp4: HD, usually sits between 54-56, I've seen it get as high as 63 and stay there for 10 minutes while the HD was idle. The HD (A WD 2500KS) sits next to the intake case fan (120 MM Antec fan)
Temp5: No clue, but it NEVER budges from 21.8 (It's the only one speedfan regularly reports with a decimal)
March 26, 2006 8:39:06 AM

my case temp is idle:32 load:38 is it normal? and in speedfan temp3 shows 83 with a burning flame icon. do you have any idea about it and is it dangereous?
March 26, 2006 9:21:29 AM

The flame is an adjustable alarm.

By case, do you mean temp 2? because if your case is 38, then that's hot. If the chip is 38, then that's fine for the Nvidia Nforce from what I've read.
March 26, 2006 9:49:09 AM

temp2 is the same temp with the system temp in thunderprobe so ı assume it is the case temp. am ı wrong?

edit: ı have 5 fans in my case it is nearly impossible for my case to be hot
March 26, 2006 11:11:37 AM

It's the chipset temp.

Odd that yours is 10C higher than mine, and mine doesn't move with system load much (sometimes it goes down even).

I think the temp sensor is just screwed up on these boards :( 
March 27, 2006 1:09:22 AM

That sounds about right.

So that's not the chipset temp then is it?

I think I can actualy adjust the tempurature sensor from the bios, I should check.
March 27, 2006 8:53:25 PM

now that I set the BIOS to shut down the machine if it goes over 70 (which should be closer to 60 given my sensor), it changes with every boot up. Seems to be all over the place. was 45.1, then 38.2, then 12.3.

It's not listed as a sensor on the motherboard, because it's listed after the HD, so it's something else. Maybe the videocard temp on bootup?
March 27, 2006 8:53:53 PM

now that I set the BIOS to shut down the machine if it goes over 70 (which should be closer to 60 given my sensor), it changes with every boot up. Seems to be all over the place. was 45.1, then 38.2, then 12.3. But it never changes unless I reboot.

It's not listed as a sensor on the motherboard, because it's listed after the HD, so it's something else. Maybe the videocard temp on bootup?
March 28, 2006 2:28:33 PM

If it's really random, then just ignore it - it's either that your probe software is probing some interrupt expecting a temp sensor and there's something else there (who knows what?), or that temp sensor is just screwed.
March 28, 2006 8:29:42 PM

ive got similar issues, but i dont have an epox board. mine idles at 40-42 and under load 50 tops. the other thing is that the board set the Vcore at 1.30 for my 3800 X2. i was pretty sure that it is supposed to be 1.35 out of the box...

anyways its OCed to 2.5 @ 1.325 Vcore and its 12 hours dual prime stable

on top of all this, when booting up, it displays the CPU temp on one of the boot up screens and it says 37C within a couple seconds of turning on the power(after it has been powered off overnight in a 22C room temp). i find it really hard to believe that it would heat up 15C in 5 seconds

the finger test is contradicting the board as well. its telling me that it is 40C and it feels about the same temp as the inner walls of the case (not hot)

o well not too worried about it, cuz even if the readings are correct, they arent high enough to cause a whole lot of concern
March 28, 2006 8:34:33 PM

I've got speedfan as well, but it reports temperatures differently since its checking sensors on an Asus mobo, not Epox. But here's what I get as a comparison.

1) Idle Temps
Temp1: 40C (This one's always 40C, Speedfan says its the ACPI temp)
Temp2: 28C (Case temp, used to be 32C before I added an extra fan inside)
Temp3: 27C (This one's a tricky one. It varies heavily with CPU load, and is more sensitive to room temps, but isn't the main CPU temp as I've checked with Asus Probe)
HD0: 29C (HDD temp)
Temp1: 32C (This is the main CPU temp, but its registered as a second Temp1... confusing...)

2) Load Temps
Temp1: 40C (Always 40C...)
Temp2: 32C (Case Temp, used to go to 42C before the extra fan was added)
Temp3: 41C
HD0: 32C
Temp1: 42C (Main CPU temp)
March 28, 2006 8:55:01 PM

the best thing to do is use your finger, they wont lie.

i use speed fan and on my lil cousins rig that i just put together for him

P4 478 northwood 2.7
ECS mobo
1gb pc2700

his north bridge temp reads 127*C!!!!!!

lol which would be melting through the board, but is quite cool to the touch.
I cant even turn up the temp on speedfan that high so that the lil flame warning will come off. it only goes to 99*C