Is my CPU too cold?!?

I wonder if anyone can throw some light on this...

In recent months, my PC has gone through a habit of locking up / crashing a few minutes after powering up. At present it's doing it consistently *every* time I run the machine. Symptons are as follows:

Fire up machine - initial temp readout is usually somewhere around 27c.

Boot machine - load an application - crash.

Hit reset button or power on / off about 3 or 4 times before machine will reboot. CPU temp is now about 35c.

Boot machine - everything fine.

It's definitely not software related - I've tried no less than three operating systems (Win 98SE, Win 2k Pro, RedHat 9). The crash will also occur if you leave it on a boot menu for a couple of minutes so it really seems like it's when the CPU reaches a certain temp.

However, when I take the lid of the box, check every cable etc, it tends to behave fine for days. The I put the lid back on and within 24 hours it's returned to usual.

Can anyone offer any suggestions?

AMD Athlon 1.3Ghz on a VIA chipset. Not overclocking, although I have had to re-house in a bigger case due to cooling issues. Could my chip be damaged in some peculiar way?

Suggestions gratefully received!

have you added anything new? does the os detect all of your ram, this could be anything, if you have a different stick of ram, or more than one stick, try one at a time, power supply could be on the way out, so could many other things, process of ellimination is your best chance here.

Wow - thanks for your quick response! I can't think of any new hardware that was added at the same time. I've upgraded and replaced a few components since then, but the problem always seems to be lurking. I might just have to try a complete rebuild, component by component (or get a new board and CPU).

I've also got some more analysis to try - think it always takes *exactly* the same amount of time before it locks up. I'm going to try with a stopwatch...

Thanks for the suggestions!

How many case fans are you running? If your saying that its fine with the case doors off and dies with them on then it does sound like a heat issue. You can never go wrong with more fans ...

I've had cooling problems in the past, so I invested in a full-tower case with an additional case fan. I've also recently acquired an additional fan so there shouldn't be an issue here. The CPU temp is stable in the mid 40s.

I don't believe this to be an overheating problem (despite my comment about the case - I think this may be something to do with my recently tightening everything up). The machine always dies when the CPU first climbs to the early-mid 30s in temperature. Once the machine has been rebooted, it can run all evening no problems.

Thanks for your input though - much appreciated!

Your processor shouldnt be overheating. those temps are relatively cool for AMD's. 45-50C is a good temp for amd chips. Make sure all your voltages are set correctly for your particluar chip. I recently bought a new Athlon 1.7ghz and it kept crashing until i found out the core voltage my motherboard set as default was too low. havent had a problem since.

I troubleshot a friends machine, doing something similar, and it was the power supply. That is what it seems to me...

This is no doubt a heat issue IMHO. Try reseating the heatsink. You may have bumped it when you had your hands in there. Use a good thermal compound like Ceramique or AS5. Make sure you clean all the old stuff off really good with some 90% Isoprpyl.

When it shuts down you are seeing a 35c reading but in fact it may be spiking higher and BIOS is telling it to shut down if your BIOS does indeed have that feature.

Also, check to make sure everything is bolted down good, ie, RAM, video board, and anything else that plugs into the mobo.

Hard Drive(s) in good shape? No wierd noises or anything?

I've a similar problem but it wasn't from the CPU ( I have Athlon 1.4GHz with 512MB PC2100 )

it was from the memory

just I remove the memory then I cleaned it

then I cleaned the memory slot also

this thing reduce the hangs by up to 70%

then I just make a Full Cleaning job to my System

the hanging stops for ever