Temperature Sensors

[mujahid7ia]

I have an Aspire X-Dreamer II case that has a front LCD display that displays the temp (F) from a sensor. I also have a Thermaltake Volcano 9 which has a sensor that can be used to control the fan speed.

Where do you think I should put the case sensor (I want to monitor CPU temp) to get an accurate reading?

Also, for optimal fan control and a cool CPU, where should the HSF sensor be placed? It came with "thermal tape", and Thermaltake suggests the bottom (pin side) of the CPU to tape the sensor. Is this a good idea?

The Thermaltake at full speed (4800 RPM) is too loud so I don't want to leave it on full.

This is my first time building a PC.

Thanks, any replies are greatly appreciated.

[SLICK RICK]

I was in the same situation as you when I purchased my Thermaltake case. I was told by another member here that it was not wise to place the sensor at the bottom of the CPU (it would not fit as shown in the manual anyway). It was suggested to place the sensor, using the tape provided, on the side of the heat sink and that the temp would only be off by a few degrees.

GOOD LUCK,

SLICK RICK

[mujahid7ia]

So, attach the Heatsink/fan sensor to the heatsink?
Sounds funny when I think about it...

Ok, how about the case sensor? next to die (someone told me this)? or just near socket?

[gmatov]

This one seems like a no-brainer, the manufacturer says to tape it to the underside of the die, the "hot spot", and you get advice to tape it to the side of the heat sink, AND are ready to take the advice.

If, for instance, your CPU is running at 55 C, that's 131 F. If you reach into the case and grasp the sides of the heat sink, you will feel that it is about 110 F,, or, regardless what it actually is, not hot to the touch. "Wow!", you say, "My CPU only gets to 40 C when I'm doing something CPU intensive. Great cooler combo. And the fan is barely spinning."

But, if you go to the onboard monitor, it will show you increasingly rising temp, because the fan sensor is fooled into thinking it is monitoring the die temp, when it is actually the temp of the great big chunk of finned aluminum, which is trying to dissipate heat, but the fan thinks it isn't hot enough to have to speed up.

There's enough trouble with onboard sensors that may not stick up high enough to contact the die, as well as chip borne circuitry that is slow on the renew.

To make it short (I know, too late for that ) put it where the mfg tells you to.

I don't know where tomshardware get theirs, but I think they use a superthin device that fits between the sink and the top of the die.

Cheers,

George

Sorry, case sensor should probably be somewhere in the airflow going to the power supply exhaust, or, if you have another rear exhaust fan, near its airflow. Monitor the temp of the air as it is nearing the outlet, rather than in one position near some heat generating item, such as a super duper vid card, which some of get so hot they need their own HSFs.

Last word, promise.

[indolikaa]

This maybe punching the obvious right in the face (or missing it entirely), but wouldn't you want your case sensor up high, and out of the flow of the case fans?

[gmatov]

Point taken. But if it's somewhere high, out of the moving air, it's measuring stagnant air, which we should, actually, be trying to get some circulation to.

A good idea would be to move it around to see if there are any hot spots, and, if there are, try our best to remedy that situation, maybe with one of the devices that fit in a CD bay, if there is an open one, to force some air to that location.

Some people leave the side off their case to aid in cooling, me for one, well, actually, I'm in the damn thing so often, it's for convenience, not cooling.

A cheap case, I don't think they do air flow studies, which are done with the case closed up.

A good case, they do, and removing the side is actually defeating all their design work.

Personally, maybe because I don't hear as well as I used to, I do not find my machines too loud. I don't go overboard to make them whisper quiet.

Hell, when I was on dialup, I even liked hearing the modems screech at each other, at least I knew mine was working..

Cheers,

George

[indolikaa]

Hell, when I was on dialup, I even liked hearing the modems screech at each other, at least I knew mine was working..

Me, too. The 'bong...bong...' when the modem would shoot for that high-speed connection was too cool.

Ah, but that was a long time ago...

[rallynavvie]

I have 8 temp sensors connected to the DigitalDoc5 on my PC. I had to actually map out where they all go. 2 of the sensors included with it were paper-thin and able to fit under the die on each CPU. The ones included with yours weren't bulbs were they? I have 6 of those type and placed them throughout the case. 1 measures ambient intake air between the front faschia of the case and the actual chassis. 1 measures air just past the primary hard drive cage to see how much the 15k RPM drives are heating up the intake air. 1 measures the air above the CPUs to see how cool the air is that their heatsinks are receiving. 1 is at the top of the case in front of the PSU draw fan. Another is on the video card's aftermarket heatsink. the last one moves around as my variable sensor. I've used it to map the airflow in my case and adjust fans as needed. I learned a lot about case cooling with fans with this device. What I've learned is I need an Asetek to be happy

Personally I'd want the sensor that came with the case to be looking at intake temps, or temps just past the hard drive cage if yours is designed with the hard drives right in front of the main intake fans. Your heatsink is only as effective as the air getting to it so keeping an eye on altered intake temps is pretty important. If you want to go nuts about it like I did be sure to get a Digital Doc5; it manages 8 temp sensors which can be tied to 8 3-wire case fans (or just monitor the fans independently), and also shows 5v and 12v rail voltages. It does take up a 5.25" bay though, but it has a hard drive cooler rack built in.

[mujahid7ia]

Thanks for the suggestions.

rallynavvie, if you were asking me, the sensors are both the paper-thin kind, not bulbs.

[gmatov]

Mujahid,

If they're paper thin, are they bare metal, not plastic coated?

If they are metal, and that thin, hunt down your directions and see if they can also be installed netween the CPU and heat sink, with Arctic Silver or some such on both sides.

That would give you the most accurate reading.

The compound will not short anything, as they are 2 dissimilar metals joinet at the end to creat a low current when heated.

Hell, I don't know how they even get them to install UNDER the CPU.. You can't weave the wires between the pins, and I don't think there is access to fish wires under the socket, as they are mounted tight to the board.

Cheers,

George

[Ripper2860]

In just wanted to make a statement in case someone reading these posts mis-interprets the phrase "between the CPU and H/S"...

Never mount something between the H/S and the CPU CORE !!

Most applications of an external temp probe, that I've seen, put the probe under the H/S, but ALONG SIDE the core. They go under the H/S and touch up along the die of the CPU core form the side. This gives very accurate readings.

I've also seen where a very small hole was dilled into the H/S just over the core and the probe placed though the hole to touch the CPU core. The hole was then filled with thermal paste or themal epoxy. This also gives very accurate readings.

Again -- NEVER PUT ANYTHING BETWEEN A CPU CORE and A HEATSINK except thermal compound.


This has been a public service announcement.

[mujahid7ia]

According to the Thermaltake instructions, it says put it on the pin side, but I don't see how to do that.

About the sensors, I guess mine aren't "paper-thin", they are plastic coated.

I think I'll put the Thermaltake one next to the die/core, but will that significatly raise temps??

[rallynavvie]

It will raise the temps that you see on your probe since it's so close to the die, yes. It won't actually affect the performance/heat issues.

There is a way with ZIF-sockets to get the probe under the CPU, I had mine set up this way before I accidentally pulled them out. Now they're attached to the underside of the heatsink near the die being held in by a piece of thermal tape rated for high temps.

[SLICK RICK]

To make it short (I know, too late for that ) put it where the mfg tells you to.

That was not an option for me, the manual for the case I have showed the sensor being place between the pins on the cpu, but for some reason, the actual sensor that came with the case was alot longer than the one showed in the manual. The only way I could have "put it where the mfg tells you to" is to literally cut the sensor and I dont think that would have been a good idea.

SLICK RICK