PC shuts down when it gets below 40 Celsius (i guess 104 F)

[lurkermihai]

OK this is the weirdest thing you've heard:
After windows is loaded CPU temp if about 43-46 C.
If i don't do anything, his temp begins to drop, and in about 10-20 sec (depending of the ambient temperature) it gets to 40 C. When it gets below, you can just count in you re head... 3.. 2... 1.. BANG shutdown (i mean brute forced, like unplugging)
If i start any program that keeps my CPU active and therefore ABOVE 40 C, the PC works fine.
Wen i close that program.. well.. you can watch it die when he goes below 40!

Mobo: geforce 6100 sm-m ECS HT 2000. CPU amd Sempron le-1100 (1800-1900 mhz)
And i have another Cpu -amd athlon 64x2 5000+
This second cpu does the same when below 54 C. To start windows with it i need to stop fan while in bios and watch it go over 54.

Now i don t really expect to find a fix here. BUT I would love a logical explanation for this....

I updated bios several weeks ago. I took the latest bios from the manufacturer web page (it's from 2008).
I also tried different multiplier/v-core voltage/fsb/HT multiplier combinations.
It is however (a little) more stable on a under-clocked multiplier. 200 X 9 (1800) seems to work better.
V-core doesn't seem to affect it. it works the same from 1.200 v to 1.350 v, below that wont start.
Except that bigger voltage keeps it hot more easy (it needs less stress to stay above 40 C).

It,s not the power supply, i have a spare too. so i'm not expecting a "IT'S THE MOBO, CHANGE IT" reply, i also guess its the mobo. I'm just curios what weird malfunction can make this strange behavior!
Ps: excuse my bad grammar.

 

[rinval]

OK this is the weirdest thing you've heard:
After windows is loaded CPU temp if about 43-46 C.
If i don't do anything, his temp begins to drop, and in about 10-20 sec (depending of the ambient temperature) it gets to 40 C. When it gets below, you can just count in you re head... 3.. 2... 1.. BANG shutdown (i mean brute forced, like unplugging)
If i start any program that keeps my CPU active and therefore ABOVE 40 C, the PC works fine.
Wen i close that program.. well.. you can watch it die when he goes below 40!

Mobo: geforce 6100 sm-m ECS HT 2000. CPU amd Sempron le-1100 (1800-1900 mhz)
And i have another Cpu -amd athlon 64x2 5000+
This second cpu does the same when below 54 C. To start windows with it i need to stop fan while in bios and watch it go over 54.

Now i don t really expect to find a fix here. BUT I would love a logical explanation for this....

I updated bios several weeks ago. I took the latest bios from the manufacturer web page (it's from 2008).
I also tried different multiplier/v-core voltage/fsb/HT multiplier combinations.
It is however (a little) more stable on a under-clocked multiplier. 200 X 9 (1800) seems to work better.
V-core doesn't seem to affect it. it works the same from 1.200 v to 1.350 v, below that wont start.
Except that bigger voltage keeps it hot more easy (it needs less stress to stay above 40 C).

It,s not the power supply, i have a spare too. so i'm not expecting a "IT'S THE MOBO, CHANGE IT" reply, i also guess its the mobo. I'm just curios what weird malfunction can make this strange behavior!
Ps: excuse my bad grammar.

from what your describing it sounds like a bios/mobo problem. did it crash prior to the bios update?

 

[lurkermihai]

from what your describing it sounds like a bios/mobo problem. did it crash prior to the bios update?

Same problem before and after the bios update.

 

[rinval]

Same problem before and after the bios update.

this is still VERY weird as most CPUS would run fantastic at 0 degrees and to see your system crash b/c its cool ... hmmm.

have you checked your bios for a max and min operating temp restriction? each bios is different but mine was listed weirdly under the HW monitor. most will not have this and it will be set by the mobo manufacturer. but it is worth looking for.

it is possible if your CPUs have over temped it could have damaged them and caused them to be unstable cool which could be leading to bios panics and hard crashes.. keep in mind amds run hot and have low temp caps.

http://www.cpu-world.com/CPUs/K8/AMD-Athlon%2064%20X2%205000+%20-%20ADA5000IAA5CZ.html
athlon 64 x2 5k shows the max operating temps between 55-70 celius.

http://www.cpu-world.com/CPUs/K8/AMD-Sempron%2064%20LE-1100%20-%20SDH1100IAA3DE%20(SDH1100DEBOX).html
smepron le100 shows a max temps of 55-65 celcius

 

[lurkermihai]

i have the bios Shut down and warning temps disabled.

 

[rinval]

i have the bios Shut down and warning temps disabled.

that is still very odd. when you boot and have the computer going have your checked your mobo,gpu hd ETC temps using something like hwmonitor? to make sure they are in normal ranges IE: 30-60 celius. your GPU may be higher.

 

[lurkermihai]

Yes, all temps are ok, except the CPU witch MUST be high to work.
I guess it really was to hot at some point and now it needs to be close to that temp to work. But don t understand why it has the same problem with my first CPU that used to work before i got into problems with this one... Maybe the shutdowns are made by a short in the cpu witch altered the mb also.
Anyway, it works very well now, as long as the fan is set to minimum.
(the dual core, over 55C) I used it a whole day with no shut down. But as a test i closed the program i use it to keep it busy at the end of the day (the AVS visualizer plugin from winamp) and it did power-off like in 30-40 sec.. WTH.. he likes HEAT then fried it shall be the rest of his unstable life

 

[rinval]

What power supply are your running and have your tried testing another one in there? Just Curious?

im thinking the CPUS are ok b/c you can boot the system and put them to work and it would seem they are stable and functional. i would try running prime 95 to see if the cpus are stable.

i would almost venture to say your mobo is acting up. im betting you dont have another one to try either.

it would almost sound like the mother board is defaulting to require the CPUs to maintain a certain temp even though you have that feature turned that off.

i would try another bios update/reflash and reset your cmos defaults then give it a try.

EDIT:

Have your tried booting the system with something like a linux live CD to see if its the OS?

 

[Terry1212]

Take a look at the motherboard and see if any of the capacitors are bulging.

 

[jdmils]

This issue wounds too much like a predefined limit is being actioned. Maybe the BIOS has a temp limit which states that it will shutdown the CPU when it gets below a certain value.

The other thing to check for is any software which is installed which may be monitoring the CPU temp and shutting down the system. I would install Win7 on a USB stick and boot off that and watch what happens there.

What does your Event Viewer show?

 

[lurkermihai]

Take a look at the motherboard and see if any of the capacitors are bulging.

Actually there are 4 capacitors that have their top a little concave, the other same size capacitors have their top convex. And those with concave tops are near the cpu soket..
They are 6.3v / 1800 uF.

 

[Terry1212]

Actually there are 4 capacitors that have their top a little concave, the other same size capacitors have their top convex. And those with concave tops are near the cpu soket..
They are 6.3v / 1800 uF.

Your motherboard is dying. Time to buy a new one. Personally, I'd either swap in a new motherboard, CPU, and RAM or if you can afford it...build a whole new computer.

 

[lurkermihai]

Your motherboard is dying. Time to buy a new one. Personally, I'd either swap in a new motherboard, CPU, and RAM or if you can afford it...build a whole new computer.

I'll try to buy and replace the Capacitors first