# Computer Q twofer: Keyboard and CPU temp
**URL:** https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080
**Category:** Factual Questions
**Created:** [September 11, 2005, 6:48am UTC](https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080 "2005-09-11T06:48:41Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@CatsCradle](https://boards.straightdope.com/u/CatsCradle)
#### Post date: [September 11, 2005, 6:48am UTC](https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080/1 "2005-09-11T06:48:41Z")
In this [thread](http://boards.straightdope.com/sdmb/showthread.php?t=329704) , I asked about my USB ports not working, and I found out that (a) my power supply went wonky, resulting in (b) my motherboard getting fried. Fortunately, the computer was still under warranty, so I sent it off to the shop. They replaced the power supply and the motherboard, and sent it back to me.
Before I forget:
CPU is an Intel P4 3.0GHz
Motherboard is an [ASUS P5GDC Deluxe](http://usa.asus.com/products/mb/socket775/p5gdc-d/overview.htm) with an LGA775 socket
So I hooked everything back up, and turned the computer on, and…my Microsoft Natural Elite keyboard doesn’t respond. _Hmm, might be something they changed in the BIOS_, I think. So I reboot and look at the BIOS settings. While in there, I checked the Hardware Monitor and discovered that my CPU temperature was at **100[sup]o[/sup]C**!
Fool that I am, I thought that it was just because the box was in a FedEx delivery truck and was hot and bothered until I released it from captivity. So I continued, and my keyboard still wouldn’t work. A bit panicky now, I went and found an old old ancient PS/2 keyboard, and plugged it in. I rebooted, and the ancient keyboard _worked_.
Then my computer shut itself down because it thought it was running at **110[sup]o[/sup]C**.
Now, the questions:
(1) Why didn’t my MS keyboard work, but the ancient one did? (_just to head some people off–yes, it’s Microsoft. Moving along…_) Both were plugged into the PS/2 port–at first I thought the port itself was bad, but the ancient one worked. I tried the MS keyboard on another computer, and it worked fine. Do different keyboards require varying amounts of power?
(2) Is it possible my CPU was really running that hot? The case was cool to the touch, and the stock Intel HSF seemed to be running okay. Just to be sure, I went out and bought a “better” third-party HSF (Thermaltake) and installed it, and it seemed to make it a bit better; idle CPU temp was now hovering between 77[sup]o[/sup]C and 82[sup]o[/sup]C. Still high, but at least it takes a bit longer before the computer shuts itself down. If the CPU were that hot, shouldn’t I be seeing the smoke coming out of the CPU already?
I’ve flashed the BIOS to the latest version, and set it to default values, and still get no MS keyboard love _and_ still have the high temps. I suspect it’s a bad temp sensor somewhere, but I’m worried that it’s not.
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### Author:  [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)
#### Post date: [September 11, 2005, 8:04am UTC](https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080/2 "2005-09-11T08:04:21Z")
How did you get into the BIOS without a keyboard?
It sounds to me as if the heatsink isn’t making proper contact with the CPU. but if you installed it twice and it’s still doing that, then I’m out of ideas.
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### Author:  [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)
#### Post date: [September 11, 2005, 11:12am UTC](https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080/3 "2005-09-11T11:12:13Z")
(1) WAG here, but the only thing I can think of is that there’s a special driver which handles extra features of the microsoft keyboard (does it have extra features?) and something in the driver got futzed up. Either that or you managed to get the keyboard controller to go out into la-la land and it recovered due to the reset when you re-booted the computer.
Keyboards do vary slightly as far as how much power they draw, but it’s just some minor variation in how much power that particular microcontroller inside the keyboard draws. Shouldn’t make a difference from one keyboard to another.
(2) It is possible for a CPU to run that hot, but they tend not to last very long at those temps. An easy way to test is turn the computer off, quickly remove the fan/heatsink, and touch the CPU. The human pain threshold for heat is around 45 deg C. If touching the CPU makes you say “ouch” then it’s hotter than 45. If I have questions about the CPU temp sensor I usually check it by putting a thermocouple on the CPU, but most people don’t have a thermocouple temperature probe just lying around.
The CPU temp will usually be significantly higher than the case temp.
Sometimes there’s a little piece of plastic film on the bottom of the heat sink to keep it clean until you add the heat sink compound. Make sure you didn’t accidentally leave this in place as it will act as an insulator and make the CPU very very hot.
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### Author:  [@CatsCradle](https://boards.straightdope.com/u/CatsCradle)
#### Post date: [September 11, 2005, 3:31pm UTC](https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080/4 "2005-09-11T15:31:59Z")
> [@Shalmanese](#):
>
> How did you get into the BIOS without a keyboard?
Hmm, I knew I got something out of order there… :smack: You’re right, I plugged the ancient keyboard in first before I looked at the BIOS.
So correct order is
(1) MS Keyboard doesn’t work
(2) Replace with ancient keyboard, reboot
(3) Check BIOS, look at settings, look at temp
(4) Panic
> [@Shalmanese](#):
>
> It sounds to me as if the heatsink isn’t making proper contact with the CPU. but if you installed it twice and it’s still doing that, then I’m out of ideas.
My next step might be to get some of that thermal paste (Arctic Silver?) and see if that helps.
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### Author:  [@CatsCradle](https://boards.straightdope.com/u/CatsCradle)
#### Post date: [September 11, 2005, 3:44pm UTC](https://boards.straightdope.com/t/computer-q-twofer-keyboard-and-cpu-temp/321080/5 "2005-09-11T15:44:46Z")
> [@engineer\_comp\_geek](#):
>
> If touching the CPU makes you say “ouch” then it’s hotter than 45.
When I removed the stock HSF I tried touching the…um, load plate (?), and it didn’t feel too hot. More like “slightly warm”. Should I try touching the CPU directly? I’m leery about killing it.