Overheating CPU

[Nocontact]

My PC has been acting very strange lately. I recently installed a new video card but I don't know if that could be related to the problem.
This morning I turned my pc on and went into the bios to see what was up, the cpu temp just started rising slowly and within 5 minutes it had gone from 33 degrees to 54. And this was just in the bios mind you.
It was also getting very hot when I played games but right now it seems just when it's idling the temps are much higher than they used to be. On startup there is no way they would get about 40-44 degrees.

I installed mobo monitor and for some reason it's saying that the cpu temp is only 32 but the bios and asus probe are both reporting much higher temps so I assume mobo monitor is acting goofy.

Can I rely on the bios for accurate temp readings?

Because the cpu temp started rising slowly but surely just by turning the pc on, what conclusion if any can I make from this?

The cpu fan seems to be spinning fine as does the vid card fan. In the bios the cpu fan was listed at about 3100 rpm.
Anyone have any suggestions?

-------------------------
Pentium 4 1.7
512 MB DDR
Asus P4S-333 DDR Mobo
40 GB HD
Win XP Pro
Asus Radeon 9600XT

 

[OldMX]

Seems like your cpu heatsink is covered with a dust carpet preventing air from fan to move between fins, causing the overheat, try a can of compressed air and spray over the hsf to remove dust and see if it makes any difference.

If the hsf is dust free you may want to reapply some artic silver thermal paste between hsf and cpu folling instructions here .

Good Luck

oldmx

 

[Nocontact]

Nope no real dust problem. Does the thermal paste wear off after a few years?

 

[BillR]

Nope no real dust problem. Does the thermal paste wear off after a few years?

It would depend on what thermal paste you used. Some of the (cheaper) silicone-based products can harden with time thus rendering them less then effective. TIM pads can virtually disappear over time.

It only takes a few moments to take it all apart, clean all the parts, remove the dust and other “stuff” that has collected on the fan and heat sink fins.

Grab some AS-5 and follow the directions on their website for reinstallation.

It’s something that should be done from time to time anyhow, this sounds like a good time to me

 

[Nocontact]

That's what I was wondering, if this is something that needs to be done from time to time as regular maintenance.

 

[Ice Czar]

what conclusion if any can I make from this?

as BillR mentioned its worth verifying the heatsink is properly mounted with a good TIM
(Thermal Interface Material, be it pad or grease)

however Id say that by changing out the video card you have added a much hotter heatsource to the case and substantially raised the ambient temperature in the case (and likely changed the airflow pattern), that inturn has decreased the efficiency of all your heatsinks and you have reached a new higher thermal equilibrium, to get back to where you were youd need to be cycling that much more air through the case, or at least a better exhausting strategy of the hot air coming off the CPU and Vidcard.

heat transfer is all about temperature differentials
http://www.google.com/url?sa=t&ct=r...lay.php?ArticleID=105&ei=UjgbQ7q2N7u6YJDa_acL

double the differential, double the heat transfered

 

[Nocontact]

The vid card has it's own fan which is running nicely, and the case and mobo temps are stable, it's just the cpu that's spiking.

 

[Ice Czar]

if the interior ambient of the case hasnt changed, and determining that from a single sensor on a mobo isnt a reliable means, then its another issue

on the otherhand if the fan on the videocard is washing over or is feeding the CPU HSF thats another matter entirely
the location of the mobo sensor may well be reading the exact same (for a given room ambient) as it was before the changeup, but then it might be in a fresh intake airstream as well

slightly edited from a different thread

while a given case, and a specific list of components and fan locations isnt necessarilly unique, it might as well be, as its not a fully modeled thermal solution (unlike an OEM machine), thus its trial and error on your part, there are substantial benefits to running cooler, if you want the components to last their full lifespan (most will likely upgrade before that however)

to answer the question, you could simply have a hot spot in the airflow pattern being picked up by the sensors in question, you could have a high ambient room temperature and poor airflow into and out of the case (you often see obstructions to airflow with cases in little desk hutches), a misbalance in airflow (over or under pressurized) or just a poor airflow pattern.

One of the advantages of a movable sensor (like in a DigiDoc) is tha ability to map your case's temperature gradients and finetune your airflow.

youd be suprised what kind of effect a simple paper duct or divider can sometimes have, or simply a small fan in the right spot, but its tough to recommend that without a personal experience of your specific config. Barring someone showing up that has a similar layout of heatsources, you need to experiment.

if you eliminate the CPU Heatsink as the issue source, and there are no addional processes adding to the workload, by a process of elimination you have reached the physical alteration of both the interior airflow pattern and the distribution and intensity of the heatsources in the case.

provided you havent overlooked the obvious, a change in the room ambient from the norm