Drastic CPU temp change after reboot... any ideas?

[JeffreyY]

Came back from work today, the temperature seemed a bit high for my liking and I was frustrated with something not working so I rebooted my computer. Now, after the reboot, running similar programs, the CPU temp is now 36 instead of around 46C before the reboot. What the hell? Anybody have any sort of explanation for this? I'm using MBM5 to monitor my Abit NF7-S.

 

[Megatomic]

Do you have an older board with an old BIOS version? Is your board a 1.x or a 2.0?

The first thing I'd do is update the BIOS to the latest version for your board revision. That may fix the flaky temp. reading.

 

[JeffreyY]

Ok, so I have a version 2.0. Does that matter? And would updating my BIOS require a floppy? I haven't touched a floppy in years so I didn't install one in my new rig. Also, does anybody know much about the tic tac BIOS?

 

[Megatomic]

No, you don't need a floppy to update the BIOS. Just get the FlashMenu133 application from Abit's website. It allows you to update your BIOS while in windows and it is very safe and reliable to use. I have used it for a year now with NOT ONE PROBLEM.

Also, I only use Abit's stock BIOS files. I get the overclock and performance I need with the official BIOS so I don't need to void my warranty by using unofficial code. But many do use it with great success. It's only really worthwhile if you want to do crazy overclocking with your board. Go for it if that applies to you.

 

[Hans5849]

there are some questions left unanswered

 

[Hyperlite]

uhh that sounds more like a sensor malfunction to me...

 

[Nebor]

You probably had some unknown application chugging away in the background, and it didn't start again after you rebooted.

 

[Zrl201]

My cpu at startup is usually around 34C, goes as high as 49C and when I come back after a long period of inactivity - 28C

I know my motherboard's sensors are correct.

 

[Delorian]

Originally posted by: Nebor
You probably had some unknown application chugging away in the background, and it didn't start again after you rebooted.

My thoughts exactly. What is your CPU usage Jeffrey?

 

[JeffCY]

Hey, this is Jeff at work

I'm pretty sure it's not a result of high CPU usage from some unknown program, but I'd have to check when I get home. To me it just seems to have a mind of its own. I was pretty frustrated when I bought 2 more case fans and after booting up with the new fans installed, MBM5 was showing higher temperatures.

How much do ambient temperatures affect the CPU temp? I live in San Jose, CA and last night I opened the windows to let the cool air in and let my comp sit idle for a couple minutes as I watched the temps, and it dropped to as low as 33C.

My other question is... how much CPU usage is required to significantly increase CPU temps? I think my typical usage is probably below 20% (web surfing, mp3's, checking e-mail, chatting). When people say load temperature, is that simply 100% CPU usage?

Thanks for the replies guys, keep them coming.

 

[Megatomic]

Originally posted by: Hans5849
there are some questions left unanswered

Of which you answered how many of?

 

[JeffCY]

LOL @ megatomic

 

[pelikan]

I get the exact same thing on my NF7-S. Many other people do too. I don't worry about it.

Edit: All the sensors seem bad to me, including the voltage ones. My multi meter tells me that the only accurate voltage reading from the board is vdimm.

 

[ROcHE]

That is a known issue with NF7-S boards. There is a little trick to lower your idle temp tough (so the difference when you reboot is smaller to non existant). It has something to do with the cpu halt function or something. I'm at work right now but I'll come back with more info when I get back home.

 

[NewBlackDak]

Mine too.
MBM 5
+3.3 reads 3.14
+5.0 readt 4.87
+12.0 read 11.80

Multimeter
+3.3 reads 3.34
+ 5.0 reads 4.99
+ 12.0 reads 12.03

Every other reboot I get good temps and the other are reading 10C off. I can't decide which one is right.

 

[JeffCY]

I've also read that nf7-s temps could be as much as 5-10c higher than actual. This combined with this inconsistency in temp readings... I don't know what to think. =P

 

[pelikan]

I don't even look at my temps anymore. I just make sure I can run prime95 overnight. If my system can do that then the temps are fine.

 

[DoctorM]

I built my system about a week ago and am using the most recent bios. Yes it's a rev 2.0 board.

Once in awhile the temperatures will look like they are 6 degrees higher than normal.
Most recently I didn't shutdown, I hibernated windows. When the computer shut down and I immediately checked the temperature in the bios and it had dropped the 6 degrees. In a couple seconds?

So on reboot, obviously all previous software was again running since it was a hibernate not a shutdown.

This is a bios problem. Abit must fix it.

Heck try running the Abit Monitor with vcool alpha 2.0 (it has nforce2 support). The numbers go batty, but MBM reads them fine.

Abit needs to do some more work, and I wish they would.

-Dr. M

 

[DaNorthface]

the motherboard bios uses the on die sensors.. so if the sensors are bad, it's the one in your chip..

 

[3LEMENT0]

I thought NF7-S v2 uses that sensor in the CPU socket? Is the temp reading from the chip diode itself?

 

[pelikan]

It uses a sensor in the socket. You can see it in there, right under the cpu die; it sticks up to touch it.

 

[JeffCY]

Well, I read up a bit on this subject. Apparently there is a cold boot issue with the NF7-S motherboards. On a cold boot the temperature is higher than normal (or in some cases lower than normal), then after a reboot it goes to normal.