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CPU temp

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March 25, 2006 9:37:31 PM

my BIOS setup says my CPU temp is 21 C and my Case temp is 31 C, Does that seem right?

More about : cpu temp

March 26, 2006 12:01:41 AM

if your temp is 21 then that is good, and the heatshink and fan are doing there job

as for the case temp, it all depends if you have extra fans blowing the hot air out dont for get the processor has the heat disppense the case does not and with hard drives and cdroms/dvd's and of course the motherboard that will all add up to alot of heat in the case.

I would not worry to much about them, most processors will run at about 40 to 47 before they get to hot, this processor before adding more thermal compound was running at 50.
March 26, 2006 3:20:23 AM

Good day

What processor are you running and on which motherboard :D 
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March 26, 2006 4:22:05 AM

Well, it doesn't seem right as 21 is room temperature and you'd have to have a pretty amazing HSF to reach that, but unless the temperature monitor is completely wack those temps are pretty great. I wouldn't really worry unless you plan on overclocking (even though systeme stability is more than temp related)
March 26, 2006 4:35:58 AM

Quote:
my BIOS setup says my CPU temp is 21 C and my Case temp is 31 C, Does that seem right?


thats impossbile
March 26, 2006 4:46:21 AM

Do you have an Asus board, Intel chip? Asus has been reporting temps lower than actual, on thier Intel mobos, to keep people from worrying.
The new chips make that backfire. Expect a bios patch in the near future.
I would complain, in hopes of speeding the process up,if I were you.
March 26, 2006 5:16:24 AM

Quote:
my BIOS setup says my CPU temp is 21 C and my Case temp is 31 C, Does that seem right?


thats impossbile

Not impossible, but extremely improbable. If he has a newer style case, ported on the side, feeding outside air directly to CPU HS, and no case fan other than the PSU fan, then the air coming in would be dumped directly to the CPU HSF where it would be heated, then drawn over the MB and out of the case by the PSU. This could conceivably cause the MB temp to read hotter than the die temp, depending on where the MB temp sensor was located.

More likely its a board or bios flaw reversing the readings or just plain screwed up.

The Antec SLK1650B has the side port and an expanding duct, but also comes with a 120mm case fan. With this case he would have had to forget to connect the case fan to experiance what hes seeing.

http://www.newegg.com/Product/Product.asp?Item=N82E1681...
March 26, 2006 8:57:26 AM

Almost sounds... backwards.

But then, my dad's XP-2400+ system reads CPU temps of idle 42C-CPU Case/MB 50C.

Only way I can tell if it right, is to put a load on it, for my dad's situation.

I suppose if you go into windows and run something CPU intensive (like Prime95) and see if the temp goes up, that would be the right sensor. As far as accuracy, I wouldn't trust it.

And if the 21C doesn't go up.. then I'd say something is wrong, or if the 31 temp goes up, then it's backwards.. heh
March 26, 2006 10:52:11 AM

wuts ur graphicx card tem say.
March 28, 2006 12:55:36 PM

lol dude thats pretty good! :lol: 
my case temp is 31 and cpu idles at 48ish, dont ask what it is under load 8O
lol i got the "presshott" p4's
March 28, 2006 3:29:35 PM

The BIOS isnt good for reading temps coz the CPU is doing very little work. If the software temp reading is higher that sounds right coz the CPU is doing more work. That is a huge difference between CPU and case temp, my BIOS sometimes reports the mobo as a couple of degrees higher than the CPU but only by a couple of degress. Try using a software temp reading to see what that states, you do need to state ur system specs though.
I have A64 3200 and A8N-SLI Deluxe, and the BIOS has only ever read it at bout 30 at the most for both CPU and MOBO. When you first turn on the PC it will be at room temp, so for the case and cpu to read so different is strange, that is assuming that your PC has only been on a short time.
March 28, 2006 3:31:54 PM

Well, I am certainly no expert, but I am a stickler for details ......... meaning, I usually take the time to document all my PC settings from the day purchased.

Based on my current temperature readings and previous experience, I quickly began to suspect temp sensors may not be very accurate. My older system gave readings that were somewhat reasonable. But my new Pentium D gives readings that are very suspect.

I have left the system down on several occasions for a 24 hour period in a 72 degree room. The moment I would switch the unit on, I began pressing F2 in order to enter the BIOS settings which takes roughly 10 seconds. The following temperatures were displayed:

CPU: 41 C or 106 F
MOBO: 25 C or 77 F
Case: 25 C or 77 F

Unless I am missing something, I honestly do not believe the CPU can heat up that quickly. I realize its beginning to heat the moment the unit is switched on, but 29 degrees in 10 seconds does not seem reasonable to me. Once up and running in Windows, I will view the Lavalys Everest system information and get similar readings ......... maybe just a bit higher, but by now the system has been running for about 2.5 minutes.

Based on my findings, I believe my CPU sensor is biased by roughly 16 degrees C. (at least when cool - not sure if the bias would be linear as it heats??) Therefore, a CPU temp of 41 C on MY unit is equal to roughly 72 F or 22 C. At least this is my belief unless someone can show me where I am in error.

Any thoughts??
March 28, 2006 3:47:09 PM

Errr.. I did this on my AMD 1ghz thunderbird, and PIII 800.

PIII 800 - Bios on startup 26C - 5 mins 36C

AMD Thunderbird - Bios on startup 40C - 50C 5 mins

I'd say each system will act accordingly. I can't remember nor took readings off my current system - P4 2.66@2.96.

I do believe that P dual would hit 41C in 10 secs.
March 28, 2006 3:56:19 PM

Well perhaps your sensors are bad, but I wouldn't doubt getting up to 41 that fast. My systems tend to boot about 5-10 degrees cooler (well I have an athlon system that boot's up at 30 and stays there :lol:  ). Plus getting to 22 is nearly impossible without some kind of phase exchanger or a nearly 100% efficient water cooling system. Unless there is a known problem like with the ASUS boards or its completely busted i would trust the sensor to +/- 5 degrees on a decent board.
March 28, 2006 4:03:16 PM

Nope.. I wouldn't say the sensors bad. Those thunderbirds run hot as hell. And I'm still using the stock hsf. :lol: 

The PIII 800 is slot. So that does take awhile for it to get up there.

I don't think anyone would want to demstrate this:

If you were to start a PC without the heatsink on, an old AMD or old socket Intel, I'm pretty sure you'll see it smoking before you start to shut it off.

I know my P4 northy will hit 40 by the time I get in the bios. Though I am folding.. would take awhile for it to cool down to do such a test.
March 28, 2006 4:17:27 PM

I have a P4 630 3.0Ghz and Asus P5GDC Deluxe MB and when I first installed I was idleing hot(upper 40's) anyhow I bought a artic cooler freezer pro 7 w/ artic silver 5 and my cpu now idles about 31C with MB reading about 30C. However, when I shut off my 120mm intake fan my MB temps can rise to 33C under full load while my cpu will drop back to 31C after I idle for a awhile. If I turn on my intake the MB temp goes back to 30C. So I think heat trapped in case from graphics card, HDD, etc. is the culprit. As far as the bios reading a few degrees hotter than in Windows, I noticed the same thing. My bios would read 35-37C after idleing for a while, and as soon as I booted into windows the cpu temp would quickly drop to 31C. My MB temp read the same either way. Drove me nuts. I looked all over for an answer and I finally got one from Asus website. Asus claims that it is normal for the bios to read higher on newer cpu's because the cpu can run in low power states(C1,C2,C3) when idle in Windows, but that the bios doesn't support these functions. Don't know if that's true, but it seems more likely than a conspiracy between Asus and Intel to quelch public outcry.

http://support.asus.com/faq/faq.aspx?SLanguage=en-us
March 28, 2006 4:24:45 PM

To give a reason why its hotter in the bios, is because its running like or similar to a DOS application. Which it will run the CPU at or near 100 percent.

When your in windows, its a different environment then DOS, so the processes will not put a full load on it, especially when your CPU load is 0-2 percent in windows.
March 28, 2006 5:10:51 PM

Quote:
tell me, do you believe if you switched on the light bulb in your room for a second then touched it it would be close to room temp. according to your logic it should be, i advise you go try it.(i dont mean the glass).


Instantaneous heat on a sensor and its ability to quickly respond is what I am questioning and your light bulb analogy may be used in this case.

If I were to switch on a 100 watt light bulb that is completely cool, the filament would rapidly increase in temperature for this is a resistive load that has current passing through it. The outside glass enclosure will have heat gain but at a somewhat slower rate. You can actually touch the glass part for a short while before it gets too hot to handle (and I do realize you stated "not the glass part").

However, I still do not believe a CPU has the ability to heat up as quickly as a 100 watt light bulb filament. If you think about it, a light bulb filament does produce light, but it is unfortunately a heating element also. For that fact, all resistive loads are heaters to some degree. I just do not feel a CPU will heat as quickly as a pure resistive load.

And then, there is the temperature sensor. I feel certain these sensors need somewhat of a brief period to react to the heat gain ......... similar to the glass enclosure on the light bulb. For these reasons, I still do not believe my CPU reading in the BIOS after just 10 seconds of being energized can escalate 29 degrees F.


Quote:
what it says in bios immediately after startup is not important. when you go into windows check using something like speefan or if like me use the software that came with you mobo. try running different programs and check cpu usage compared to temps.


The temperature at startup probably isn't important, as you have stated. But, it is a good reference for me to check the sensors integrity ..... at least I would think. For this is when I truly know the temperature of my system. It has been down for 24 hours and must be at room temperature also. As I stated in my previous message, I also use Everest system information software as you have suggested. According to other posters, and there is some disagreement, the BIOS readings should be the most accurate. I have found the BIOS and Everest readings agree fairly well! So, I see no reason not to use my BIOS values as a reference.
March 28, 2006 5:45:20 PM

I wasn't saying that his sensor was busted, just that its highly unlikely...

Also the bios setting can be most accurate however they need to be calibrated correctly (sensor temp vs die temp, dc offsets, etc). I have a couple of MSI boards that where reporting temps +10 C higher than they should have, until I updated the bios.

Expecting your system to startup as room temperature is a mixed bag. Just remember that your heat exchange efficiency with the air goes something like delta T^4 so your heat exchange is difficult at low temperatures.

Someone actually did this with a thermo diode on a 300 MHz:

http://www.analog.com/library/analogDialogue/archives/3...

Just look at figure 4a and tell me you trust the sensors 10s after startup (keep in mind you don't know that your system has a that amount of therma lag).
March 28, 2006 6:10:50 PM

I never said anything about his sensor being busted. I was talking about mine, reaching 40C in about 10 secs at room temp.

If you don't have a good heatsink, like the stock HSF on my AMD thunderbird... you don't think its possible to get to 38C-40C in around 10 secs?

Or the other guy that replaced his HSF with the 'artic cooler freezer pro 7'. He noticed a difference in the heat dissipation, and showed lower temps then his Stock HSF.

I can understand that it (sensor) may not tell you the exact temp, but that is all you have to understand how hot it is getting around. I wouldn't advise putting your finger on the die to check to see if its warm yet. :roll:

I can also understand the bios updates are needed, and things will be off because of the manufactor. I can tell you all my bios's on all 3 computers are up to date. I pretty much trust what they tell me.

Here's a link to mess around with. Not sure if anyone has see it.

Neat script for - Calculate Your Overclocked Wattage:

http://www.benchtest.com/calc.html

It doesn't have all newer CPU's. But if you put in your specs, should help give you an idea the wattage your CPU might be doing.
March 28, 2006 6:18:59 PM

I have no idea if this is fully correct, but I understood that newer P4 had an on-die thermal sensor that reports to the MB hardware monitoring chip. One would think that this would be more accurate than a thermal coupler placed near the heatsink. According to Asus, the software Asus Probe 2 reads its temps from this same hardware monitoring chip as does Everest, so you would think they would all be the same. As for the bios reading, it seems it is higher because of the power states of the cpu. If I auto-execute Asus Probe 2 to start with Windows, I can actually watch the temps drop immediatly after booting into Windows. After that I can open both Asus Probe and Everest with identical readings.
March 28, 2006 6:23:27 PM

Yeah I argee with you 40 C in 10s is completely possible if not probable with a cheap heatsink. I was just responding to the theory that you can calibrate your motherboard sensor by cooling the computer. Thanks for the link, I hadn't seen that before.
March 29, 2006 2:00:25 AM

Quote:
Nope.. I wouldn't say the sensors bad. Those thunderbirds run hot as hell. And I'm still using the stock hsf. :lol: 

The PIII 800 is slot. So that does take awhile for it to get up there.

I don't think anyone would want to demstrate this:

If you were to start a PC without the heatsink on, an old AMD or old socket Intel, I'm pretty sure you'll see it smoking before you start to shut it off.
I know my P4 northy will hit 40 by the time I get in the bios. Though I am folding.. would take awhile for it to cool down to do such a test.


Sadly, I can confirm this. About a year ago I built a new system using a brand new thermaltake 80mm CPU HSF on a 2800XP. The cheap-arse HSF fan failed to seat properly which I didnt figure out until it was to late. On the first start up and the processor blew in about 2 seconds. No smoke, just "POP" . The smoke came after it was to late. Ruined my perfect 30+ build record :cry: 
March 29, 2006 10:13:09 AM

Quote:
Quote:
Sadly, I can confirm this. About a year ago I built a new system using a brand new thermaltake 80mm CPU HSF on a 2800XP. The cheap-arse HSF fan failed to seat properly which I didnt figure out until it was to late. On the first start up and the processor blew in about 2 seconds. No smoke, just "POP" . The smoke came after it was to late. Ruined my perfect 30+ build record :cry: 


Well, I guess I stand corrected in my theories. I would have never thought a CPU would heat that quickly. So, based on what I have learned here, if a CPU fan were to ever fail or the HS became unseated, there would be very little time left for the CPU ........ it would over heat very rapidly and then die. Correct??
March 29, 2006 11:10:16 AM

The older CPU will burn up, if the HSF is not installed properly.

If it is installed properly, if the fan fails, the processor will just run hotter then normal. Basically, the system will not run stable, or if it is cool enough to run, may corrupt data, when the usuage increases to 100 percent.

If it is continued to run hot, it will eventually fail. (CPUs with no throttle) As well as melt the plastic grid which it sits on.

Newer CPU back throttle to keep from burning up. It is a feature back safe guard against burning it up.

The bios hardware health monitor, if setup right, will shut down the PC if thermal limits are reached. But a bios can't protect a CPU if it is not installed properly with a HSF, and burns up in a matter of sec, without any throttle back.

That is my understanding of it all.
!