My computer is so hot but not in a sexy way.
 

My computer is so hot but not in a sexy way.

Lately, I've been getting warnings during boot up telling me to check the "power" tab in my BIOS. Every time I do so, the CPU temp is either at or heading to about 140 F.

Surely that can't be a normal temp, could it? I don't recall it usually being that high.

I've not changed anything in my hardware. I have the same power supply (500 watts, I think) same CPU, motherboard, ram, etc. The computer is plugged into the same place in the wall.

When I opened the box and separated the CPU from the CPU fan, I noticed what appeared to be a "dried smearing" where the two contacted.

If I recall correctly, my brother put some cooling paste there years ago when this box was built. If that is the case, then would putting fresh cooling paste there bring the temp down?

If that is not the case, then what suggestions do you have to remedy this hot CPU temp?

Thank you a bunch!

What kind of CPU? Make a difference. Mine is running at 130F right now and I'm not worried. More "powerful" CPUs like my x86_64's can run even hotter under heavy load. I'd be surprised if 140F is approaching the design limit of the CPU, but, again, it depends on the CPU.

Maybe it has always run around 140F and you've just now noticed? If you use some sort of supervisory app like gkrellm or conky to monitor temps and you've noticed an increasing trend in CPU temps for the same load, there might be a problem.

If you pulled the heat sink off the CPU you absolutely need to replace the thermal grease as soon as possible. You'll need to thoroughly clean the old paste off both the heat sink and the CPU. Follow the application instructions with the grease you use. The whole point of the grease is to fill in the micro-scratches on the mating surfaces to provide maximum surface area for heat transfer. The grease is thermally conductive, but not as thermally conductive as the metal case and heat sink. Too much grease will cause your CPU to overheat as quickly as too little.

If you determine 140F is abnormal and new grease doesn't help, first consider what has changed recently. Did you move the case to a new location, is there something running on your machine that is heavily loading the CPU? If it's not something like that, look at the CPU fan (does it really work), airflow internal to the case, and the dust-bunny factor on the heat sink. If the heat sink looks like it's growing hair, you need to clean it.

Agreed, also, I would use 100 % isopropanol to clean it off, it works very well and will not damage components like water-based solvents. Use only a little, and make sure the power is off (duh).

Oh, and I would use a silver-based compound instead of grease ... it gives lower temperatures.

Ethanol is good for drinking, but it's generally not recommended for cleaning electronics because it is acidic and can lead to degradation of the components. Follow the instructions provided by the manufacturer of the grease you choose. Most likely they will recommend isopropyl alchohol.
If you choose to use a metal-based grease, which I would also recommend as it has a much higher thermal conductivity than ceramic-based greases, be EXTREMELY careful not to get the grease on any electrical surfaces. Metal-based greases are, obviously, electrically conductive as well. If the grease bridges the pins on the processor, for example, you stand a good chance of a short circuit.

oh yeah, it is isopropanol (I have a bottle here), sorry about that.

Wow...thanks for all the replies.

weibullguy, you bring up a good point. It is possible it has always run around 130-140 and I simply never noticed.

My cpu is a 2.4 ghz (single core) pentium. I don't recall the bus, etc.

I did give the box a good dust cleaning but that did not alter the temp and I did not expect it to do so. I keep it quite clean.

For any and all to answer: I've never applied cooling grease, gel, or whatever it is called. Is there a certain method? Do I just use my fingers? Do I put it on a Q-tip and gently swirl it? I assume once I put it on and reconnect the CPU and heat sink, it should act as a "cement" and keep the both the CPU and heat sink "glued" to each other. Is that correct?

Thanks again!

Application methods vary, but whatever you do, do NOT apply too much, it will have the opposite effect that you want and act as an insulator. What I do is put a small drop in the center and then press the two parts together. If you do it this way, make sure the paste does not run too close to the edge.

See this article for the effects of different techniques:
http://benchmarkreviews.com/index.ph...1&limitstart=4

The purpose of the paste is to fill in small irregularities in the metals which hold air pockets. Air is a poor conductor of heat, so instead that small space is filled with a silver compound (best heat conductor):
http://benchmarkreviews.com/index.ph...1&limitstart=2