computer overheating & extremely loud

[Redhunter]

I built this computer about 6 months ago and it's been running great...up until about 2 weeks ago. Now for some reason after it's been on for a few minutes it sounds like the cpu fan is starting to spin faster and faster, thus getting louder and louder, until the sound can be clearly heard in other rooms. This is only made worse by the vibrations as well. Another thing that doesn't make any sense is the fact that I can leave my computer off for an entire day, and when I turn it on at night the cpu temp starts up at around 50-60 degrees celsius, which never used to be the case. I pulled everything out and thoroughly cleaned it, but that didn't work.

I have no idea what could be causing this. I just bought a new case (my old one had 3 120mm fans and it started doing this while I was still using that case). Now I'm using an antec case and it's still doing it.

Pentium 4, 3.0 GHz
1GB Kingston Ram
Radeon 9800 Pro
Asus P5P800 motherboard
SmartPower 2.0 450W ATX12V v2.01 power supply
Antec Sonata II case

Edit: One other thing that has me confused is how my computer is doing all of this, yet it never actually shuts down or freezes up on me (just gets a little sluggish if I do actually stay on it for a while)

 

[Ice Czar]

the room is likely hot

cut & paste 101
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

there are three basic components to any thermal solution:
the heat transfer interface
(in this case the heatsinks total area for the CPU, GPU and in the PSU)

the heat transfer medium's volume\pressure to time
(in this case airflow, with additional variables like airflow resistance)

and the temperature differential
(where using cooler air has a huge impact)
while the total heat generated by the various heat sources based on how much work they are doing is the high side of a temperature differential, by employing a cooler airstream you have the option to lower the lower side of the differential, conversely your able to move less heat in the same timeframe as the differential decreases

a real good computer oriented guide to thermodynamics
General Heat Transfer Guide

Heat transfer is all about temperature differentials. Conduction through materials and convection away from surfaces is proportional to the temperature differential that exists. Basically the thermal resistance of a given solution changes with the temperature differential, which is why thermal solutions are rated in °C/W which leaves that variable ambient open but gives you a formula

The heat transfer through the wall follows a simple equation:
Q=k/L(T1-T2)

We can draw some interesting conclusions from this equation. First, heat transfer is proportional to the temperature difference on the object. If the temperature differential doubles, the heat transferred doubles. Second, the conduction coefficient "k" is proportional to heat transfer. If the conduction coefficient doubles, the heat transfer doubles Alternatively, for the same differential temperature, twice as much heat may be transferred. The final observation is "L". As thickness increases, heat transfer decreases. Alternatively, to maintain the same heat transfer through a material twice as thick requires twice the temperature differential.

while that addresses conductance, there is a corrallary for convection (transfer from the heatsink to a fluid (air\water\ect)
its known as Newton's Law of Cooling
>>>.>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

in short when the room temperature gets too hot you can overwhelm your thermal solution
(and that includes everything from phase change to H2O to air)
and since the fan your hearing is likely temperature controlled, its trying to compensate for the decrease in the temperature differential with more airflow

now if there really hasnt been a change in the temperature differential
there is a hardware malfunction, the fan itself could have a bad bearing, the fan contoller could be the source ect. Point is you need to adjust your observations to a finer resolution that takes the ambient into account because of the massive influence it has.

 

[Redhunter]

lol alright, thanks for the fast reply.
I think I understood most of that

I doubt it's got to do with the room, because the temperature has been fairly constant the last few months (and even hotter in early may) and I never had any problems.

If there was a problem with the fan itself, why would the cpu start up at anywhere from 50-60 degrees celsius?
I typed my original post on the computer I'm having problems with and had to switch to a different machine because it was getting too loud for close to 1am. I checked this one out when I first turned it on and it was around 30 degrees celsius.

Another major thing I noticed when I turned off my computer was the power supply. It was extremely hot as well when compared to this one. I could basically feel the heat through the top of my case :s

 

[Ice Czar]

well Id say you need to start isolating the issues
do you have a PSU that will run the problem box?

If that is a source of "extra heat", generally meaning its not fullfilling its exhausting duties
though its possible it is degraded, swapping it out might reduce the CPU fan speed

then there is the forest for the trees question
are you sure its not the PSU fan instead of the CPU fan?

or
do you have another CPU fan available?
for testing