A question about my temperature sensor.

[DalamarD]

First of all, I apologize in advance for the rather n00bish question, but I'm somewhat new to the PC building scene.

I just recently put together my first system, and everything works great. However, my case has a temperature display on the front and the temperature is based off of a little sensor attached to a wire in the case. My question is: where exactly should I put this sensor for the best temperature readings? Right now I have it sitting up against the heatsink on the processor. I'm not overly obsessed with the temperature or anything, and I'm not overclocking to the extent that I'm worried about things overheating. I'd just like a decent idea of where most people put their temperature sensor for good general readings so I can adjust my fan speed as needed. Thank you in advance for any assistance.


DalamarD

 

[Fullmetal Chocobo]

I wouldn't consider that a noob question at all actually, considering you are asking as a matter of survey of where people put there stuff. Now if you asked how, that might be a different question.

If I only had one, I'd probably put it right where you have it. I also might consider putting it at the intake or exhaust of the computer, to see how temps are going in one of those two places...

And congrats on building your first successful machine!
Tas.

 

[Bona Fide]

Mine has two temperature probes, so I put one near the heatsink like you, and one near the Northbridge. This gives a good idea of the CPU temps and the mobo temps. But if you only have one, the CPU is more critical. Place it as close to the actual chip as you can, since the heatsink's job is to draw away heat, and might not give accurate readings.

 

[DalamarD]

Thank you both very much for the assistance. I guess I'll just move it a bit closer to the center of the heatsink so it's near the processor more. Thanks for the help!


DalamarD

 

[Lazien]

For the best results I would put it under the actual processor. Pop off the heatsink and take out the cpu then place it on the socket under were the core would be and then reinstall your cpu and heatsink. As for accuracy's sake that would be the best spot since air movement would be zero you would get a true cpu core temp.

 

[CrispyFried]

Originally posted by: Lazien
For the best results I would put it under the actual processor. Pop off the heatsink and take out the cpu then place it on the socket under were the core would be and then reinstall your cpu and heatsink. As for accuracy's sake that would be the best spot since air movement would be zero you would get a true cpu core temp.

That is not a good idea, its a great way to kill the CPU and probe though.

I have 4 probes: CPU heatsink, GPU heatsink, near an exaust fan and on a mem stick heat spreader.

 

[imported_rod]

Originally posted by: Lazien
For the best results I would put it under the actual processor. Pop off the heatsink and take out the cpu then place it on the socket under were the core would be and then reinstall your cpu and heatsink. As for accuracy's sake that would be the best spot since air movement would be zero you would get a true cpu core temp.

How could you reinsert the CPU with a temp probe in the way?

I've heard installing it between the CPU and heatsink is the best spot, but I've never actually done it, so Im just going by what i've heard.

RoD

 

[CrispyFried]

Originally posted by: rod

How could you reinsert the CPU with a temp probe in the way?

I've heard installing it between the CPU and heatsink is the best spot, but I've never actually done it, so Im just going by what i've heard.

RoD

Thats bad also, the probe is too thick, as well as being crushed it will interfere with the heat transfer. Any gap between the HS and CPU is Bad. Another great way to kill your CPU and probe.

I had a 486 heatsink with a detent for a probe, but Ive never seen one since.

In the heatsink fins is fine, if you want the most accurate reading use a spot of thermal paste and place it near the center at the base. Even then it will measure a combo of the heatsink and the air blowing against the probe.

 

[Elcs]

Originally posted by: CrispyFried

Originally posted by: rod

How could you reinsert the CPU with a temp probe in the way?

I've heard installing it between the CPU and heatsink is the best spot, but I've never actually done it, so Im just going by what i've heard.

RoD

Thats bad also, the probe is too thick, as well as being crushed it will interfere with the heat transfer. Any gap between the HS and CPU is Bad. Another great way to kill your CPU and probe.

I had a 486 heatsink with a detent for a probe, but Ive never seen one since.

In the heatsink fins is fine, if you want the most accurate reading use a spot of thermal paste and place it near the center at the base. Even then it will measure a combo of the heatsink and the air blowing against the probe.

I believe with thin-headed probes, It was possible to place a probe touching the outside edge of an Athlon XP core without interfering with the heatsink or thermal contact.

With the new age of heatspreaders, I dont think its possible in that way. Id guess the best place for a probe to gauge CPU Core temps would be in between the fins of the heatsink, right on top of the core but even that wont give you a decent reading, especially throwing dual core madness into the fray.

 

[CrispyFried]

Originally posted by: Elcs

I believe with thin-headed probes, It was possible to place a probe touching the outside edge of an Athlon XP core without interfering with the heatsink or thermal contact.

With the new age of heatspreaders, I dont think its possible in that way. Id guess the best place for a probe to gauge CPU Core temps would be in between the fins of the heatsink, right on top of the core but even that wont give you a decent reading, especially throwing dual core madness into the fray.

Thats true, I was think mainly of CPUs with full heat spreaders. My probes are pretty thin but they do say never to put them between the CPU and heatsink.

The probe in my CPU HS reads about 15 F cooler than the on board probe. I just put it down to air flow and the HS doing its job.

 

[Lazien]

Originally posted by: CrispyFried

Originally posted by: Lazien
For the best results I would put it under the actual processor. Pop off the heatsink and take out the cpu then place it on the socket under were the core would be and then reinstall your cpu and heatsink. As for accuracy's sake that would be the best spot since air movement would be zero you would get a true cpu core temp.

That is not a good idea, its a great way to kill the CPU and probe though.

I have 4 probes: CPU heatsink, GPU heatsink, near an exaust fan and on a mem stick heat spreader.

Well I'm sure Your right CrispyFried. I mean there is no way Thermaltake would advise something that would destroy ones CPU would they?

DalamarD check the following link (pic 2) to see what I meant since I had no way of knowing which CPU You have, but it's up to You wether You believe Thermaltake or CrispyFried.

http://www.thermaltake.com/support/installguide/coolers/a1901221516xbpro.pdf

 

[CrispyFried]

Originally posted by: Lazien

Well I'm sure Your right CrispyFried. I mean there is no way Thermaltake would advise something that would destroy ones CPU would they?

DalamarD check the following link (pic 2) to see what I meant since I had no way of knowing which CPU You have, but it's up to You wether You believe Thermaltake or CrispyFried.

http://www.thermaltake.com/support/installguide/coolers/a1901221516xbpro.pdf

I notice thats a particular Tt heatsink kit. The HS overlap and probe wire/sensor size is known, since its all Tt and made for that particulat application. Since DalamarDs setup is a different HS and probe, following that advice is most likely suicidal. If you want to try that with your probe/HS feel free, but you should stop giving advice that may well destroy someones CPU. With my HS and probe size, my P4 would be toast if I tried that.

Lazien, do you have any probes in your case? If so where and how are they mounted? I have 4 I use from two different manufacturers (Tt Hardcano 10 and Maddog(?)) and both stated not to mount between the CPU and HS. My Tt Smartfan II also has a thermal probe on a lead (I dont use it) and it also stated not to mount between the HS and CPU. Nothing was mentioned about threading through the pins to get to the underside but the wire size is obviously to large for that anyway.

 

[Lazien]

It should be said that many thermaltake heatsink/fan combo's have that same probe placement suggestion in their instructions. What I think is funny is that when You dont understand something You immediately say it's bad and will burn up Your pc. You need to get a clue and understand that an insulated wire a couple hairs in width WONT burn up a CPU just because it's underneath it LOL. Furthermore, the end of the probe (as with many average probes) is flattened to less than about 0.1mm....I dont see how that could possible hurt ones CPU being under it but then again You do have 4 of them so You must be right.

I have a probe directly under My cpu's core for temp readings and it's been going for almost 6 months without frying anything. If You'll notice I have an AMD FX-55 also, A cpu that would surely burn up given Your stellar advice, but then again it sounds like You know everything because You have 4 so I guess I should just shut up since I have a paltry 2.

Oh, did I mention that I spent 4 years in the military as an AT/Cal-Tech (and TTU 205 cert.) with My micro minature soldering cert (2M).....then after that I got a bachelors degree in electronic engineering but then again I'm sure Your 4 probes dwarf that as well.

I didn't intent this to be a flame in anyway, shape or form CrispyFried and I will take the blame in assuming that DalamarD had a probe similiar to mine in design (which is fairly standard if on the thin side), I did recieve it with My fan after all so I thought it a rather common design....hell I have about 6 of them that came with many fans over the years.
I might be new to watercooling pc's but I surely know My way around electronics.

To make a long story short it's a joke to place it under the core with a touch of tape and re-incert the CPU without problems at all. Ofcourse, if You go ahead and bend pins or some other stupid act then yea You'll wreck Your CPU.....just be careful and all is good.

In the end CrispyFried I apologize if I offended You.....but remember, if You live in a glass house You shouldn't throw stones.

 

[BeakerChem]

On the same topic, I am trying to figure out where to put a temp sensor on my 7800GTX. There are heat pipes on the side of the card, but I can't get the themal tape to stick there, so I put it as near the exhaust fan as I could over the plasticy type top cover. I get 38C under idle and 48C under medium load.

Any thoughts on my placement?

 

[CrispyFried]

Lazien, I have no problem if someone carefully tries that and suceeds WITH THAT PARTICULAR SETUP (sorry for caps, just want to make sure you know thats a whole kit specially designed that way for that application), but if someones new at it and doesnt take proper precautions there will be problems with an unknown HS and probe size. Instead of the probe being along side the cpu under the HS overlap it might actually go in between the CPU core/heatspreader and crush the probe. Without proper core to HS contact due to the probe the core will overheat, hopefully it will throttle down before damage but why tell someone to take the risk? On your system thats fine, but I have a problem telling someone of unknown skills and an unknown setup to try it.

On my probes the instructions (the two Tt probes, from the Hardcano 10 and the Smartfan II plus the DD probes) they specifically say NOT to put the probe between the HS and CPU, mainly because they can not assume the person will slide it in from the side properly (or mount it on the HS overlap area IF there is an overlap) and not actually get it between the CPU and HS. And my probe leads look too thick to thread it between pins, perhaps because the P4 pins are closer than the AMD. Or perhaps they arent but none of the instructions I have (3 different ones) say to try that.

The prob in that setup looks far thinner (wire size) than the probes that came with my 2 Tt units and the DangerDan probes. They (that HS kit setup) look specifically designed for threading between pins and sliding under an overlarge HS (footage wise, so it overhangs the heat spreader) so thats why they say that. Generic probes are different. Since neither you nor I know DalamarD specific HS and probe size, I elect to err on the side of caution.

So that is why I said what I did. No offence taken. But I hope you realize that not all setups are like you describe. I do, and allow for a generous amount of error so no one will damage anything.

 

[Lazien]

Well I never said to have him put it "between" the heatsink and cpu, I told him to put it under the cpu. That's a world of difference. Just about any moron who reads these forums should know better than to place anything but thermal paste between a cpu and heatsink. I hope My instructions don't imply that I said to put it between the heatsink and cpu because that's just stupid.

 

[CrispyFried]

Originally posted by: BeakerChem
On the same topic, I am trying to figure out where to put a temp sensor on my 7800GTX. There are heat pipes on the side of the card, but I can't get the themal tape to stick there, so I put it as near the exhaust fan as I could over the plasticy type top cover. I get 38C under idle and 48C under medium load.

Any thoughts on my placement?

I havent seen how that is setup but is there anyway to actually get the probe into the exaust air from the fan without interfereing with anything or obstructing air flow? That may be more accurate. If it looks like it could hit the fan or anything do try that though.

 

[Lazien]

What I would do to get the most accurate possible readings from My probe (knowing they arn't accurate for jack in the first place) is pop off the retention plate on the "backside" of the card and place My probe "Intelligently" between the retention plate and the backside of the card under were the GPU core would be. Now by intelligently I mean dont stick one of those round thermometer looking probes back there and screw down the retention plate or anything else that just dont seem right. Get one of those nice flat probes that many online retailers sell and carefully stick it under the retention plate as far as the flattened out tip will go. This placement should dramatically cut down on erroneous readings and temp. spikes from air movement around the card and give an all around more accurate reading than sticking it on the heatsink.

That is what I personally would do...Yes I have done it before on My cards and Friends cards and will continue doing it. I have yet to burn up any cards and doubt I ever will.

But if You go and shove a bunch of bare wires under there and wonder what happened see the section above on intelligence

 

[CrispyFried]

Originally posted by: Lazien
Well I never said to have him put it "between" the heatsink and cpu, I told him to put it under the cpu. That's a world of difference. Just about any moron who reads these forums should know better than to place anything but thermal paste between a cpu and heatsink. I hope My instructions don't imply that I said to put it between the heatsink and cpu because that's just stupid.

You didnt say to put it between the HS and CPU (well along side it really), the instructions you linked to said to do that with some CPUs. I talked about that because those instructions mentioned it and I wanted to point out potential problems.

As far as mounting under the CPU, with that Tt kit its possible but Id like to point out a potential problem with that if done with generic unknown HS/probes. This is not directed at you Lazien, just a point to consider for anyone who may try that it.

If the probe wire size is too thick, even if it threads between the pins OK, the CPU will probably not sit flat (or sit too high) in the socket due to the wire size preventing it from seating fully down. Since its supposed to be flat and fully seated when the HS is mounted you may, depending on the mounting design, put too much pressure on the whole CPU or on one side. Or the HS may not mount flat against the CPU.

Again, what may be OK in that particular HS kit may not work well or at all with other HS and probe designs.

I point this out in the interest of safety and reliability, not as a flame. Just something to think about.

See my sig if you want to know why Im a stickler about stuff like this

 

[Lazien]

You are right CrispyFried and now that I think of it, when I put the probe under My FX-55 I noticed that it was rocking just a touch, so I removed the heatshrink tubing from the wire connections at the tip and sprayed conformal coating on it instead so the CPU would sit flat (since it's much thinner now).
I will have to admit that things that seem like common sense/knowledge to Me are most likely not to others without My background. Your point is taken CrisyFried and I will try to remember to explain much more throughly any future posts.

The following pic shows a good spot if Your cpu does not have a heatspreader.....what new cpu dont though? Hence the reason for My original post on probe placement
http://www.extremeoverclocking.com/reviews/misc/images/CompuNurse_5.jpg


F Y I

This link will explain why a thermister type temp. probe can never really be accurate because of the non-liner resistance drop and inherent interpolation mathematically of that resistance drop by the control unit. Most of the "freebie" ones You get with fans and such have no were near the accuracy of this probe by the way....that's why You can't go by someone else's temps even if their setup is EXACTLY the same as Yours. With freebie probes 1-3C differance between setups is statistically the same.
http://www2.vernier.com/booklets/sts.pdf