ForumsITGeneral • Why does my computer get Hot
By: adrianswift
Why does my computer get Hot anyway?

Thermo-dynamics. That’s why.
Computers and their components are made up of resistors and capacitors and such. All of which have some sort of electrical current flowing through them. As we all know an electrical current does not flow 100% unimpeded, there is always a measure of resistance. There are times when we want resistance, a resistor for example, or an incandescent lamp.. These are designed to restrict the flow of electricity but still let a predefined amount through. Resistance causes heat…
If anyone doesn’t already know, both of these examples can get ‘warm’ to the touch.
Physics!.. Thermodynamics; or to be more precise the law of conservation of energy. This states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but cannot be created or destroyed.
So we have a circuit with a resistor in it, when energy flows through it we can see some of it would be “lost” because of the resistor. However it is more precise to say that the energy isn’t lost, it is simply converted by the resistor into a different form of energy, Heat in this case. Much like a light bulb, the filament is highly resistant and so generates a lot of heat, so much so that it glows.
In computing we tend to think of low voltages but the days of the low wattage computer processor and the Atari 2600 are gone. A lot of modern processors in computing are around 95Watts or more (your average house light bulb is around 60Watts for the old incandescent). All that energy is being used in a tiny space less than an inch in size. All that energy is in the processor running through countless transistors. Now consider that in a modern processor there is between 1 to 2 Billion transistors.. all generating a little bit of heat as the energy is transformed. The harder you make the processor work, the more energy it uses and the more heat is produced.
How hot can it get?.
Hot enough to melt the fragile transistors inside the CPU, which is why they need active cooling these days. Cooling is generally in the form of an aluminum or copper block with fins which draw heat away from the processor and a fan to move the radiant heat away from the fins.
September 17, 2014 at 9:18am
By: johnsams
Heat is the enemy of many electronic devices and at times I miss the bad old days when things like air conditioning was set according to the equipment needs instead of the people working around them. When most people look at a computer, they do not know that inside that box is a chip that has been carefully constructed out of silicon so it does not use what we used to call discrete components but has those billions and billions of transistors inside of it. Space requirements down, more heat in a smaller area, better and more targeted cooling requirements needed, both for the processor and for the low voltage power supply.
September 17, 2014 at 3:09pm
By: eddieng
Very informative. Thanks. Are there cases where someone might need more than just the fans to cool off these components?
September 17, 2014 at 3:12pm
By: sawyerzent
Question: I know that excessive heat could lead to increased wear or failure in the electrical components. I used to have one of those smaller laptops that would overheat easily, and this would in turn cause a drastic reduction in performance. When I used a laptop cooling pad it would work fine again. What is going on here? Is the heat causing the components to work slower? Or is it that the computer is programmed to do less work to prevent failure?
September 17, 2014 at 5:39pm
By: eddieng
Also, is it possible for computers to be too cold? Would it affect the electrical signals at all?
September 19, 2014 at 3:17pm
By: johnsams
Electrical current causes heat to be created. The heat if not dissipated will cause the components to heat up and as they heat up they offer more resistance to the flow of current, as in computers, it will actually caused them to slow down because of the additional resistance from the heat produced. Colder is always better, the electrical signals would not be effected. The cold would effect the materials the computer was constructed from more than it would effect the electrical signals. The next big front in electricity and electronics, the development of a superconductor that operates at room temperature.
September 19, 2014 at 3:48pm
By: sawyerzent
Oh I see, that almost seems counter intuitive since heat usually speeds up reactions, and other physical phenomenon, but it slows down the electrical signal?
September 19, 2014 at 5:12pm
By: eddieng
That's a lot of helpful information. Thank you for responding.
September 22, 2014 at 2:58pm
By: johnsams
Yes that is correct, heat slows down electrical flow and causes even more heat build up. Conductors allow electrical flow, but the amount of flow they can handle is based on the physical size of the conductor, the smaller the conductor the less current flow and the wiring inside a computer is quite small. Current flow decreases because the conductor is now operating in a temperature range that is outside where it can perform well.
September 22, 2014 at 3:16pm
By: jennciurla
That makes a lot of sense, and thanks for the useful information, as always John!
September 23, 2014 at 10:13am
By: johnhoover
By: eddieng - "Very informative. Thanks. Are there cases where someone might need more than just the fans to cool off these components?"

Yes, there are a number of different applications that require computers that either need to be kept at temperatures not possible through air cooling (e.g. high-end gaming systems) or are not compatible with direct air cooling.

In these cases, liquid or water cooling is often necessary. These systems work similar to the engine cooling system in your car. Heat is removed by a cooling system that circulates water, or another liquid coolant, through the computer. As the liquid circulates through tubes in the computer it passes through a heat exchanger (the radiator on your car).

These systems are much more complex than a simple air system and require components such as heat exchangers, tubing, circulating pumps, and a liquid reservoir.
September 23, 2014 at 1:55pm
By: johnsams
Very true, John, but have you ever work with an electronic system where the components were in direct contact with the liquid cooling medium? I have. Used pure distilled water, very high resistance to current flow. Still needed a lot of additional equipment.
September 24, 2014 at 3:04pm