When computers are working hard, such as when playing games, video editing and other processor-intensive activities, you may have noticed that it gets quite hot. You can feel the heat through the computer's case, the fan blows out hot air like a hairdryer, and laptops start to burn your legs. Is it too much to handle?
Heat build up has always been a problem with processors right from the start. Overheating was just as much a problem 20 years ago as it is today. The faster the CPU is clocked, the more heat it produces, and the more work it has to do, the higher the heat output.
This is why processors have heat sinks on top of them and fans to blow cool air over them. It is normal for a processor to get hot, but it can only handle so much heat.
If a CPU overheats then several things can happen. These days a computer will monitor the temperature of the processor and there are temperature sensors actually in the chip itself. If it did not have this or if the system is faulty then run-away temperatures would fry the chip eventually and it would die.
Fortunately, this is not likely to happen on a recent PC because when the system detects that the CPU is overheating, it is possible to shut down the computer. Just think, have you been using your computer to play games, video editing, watching online videos, playing online games and so on, and the computer has just switched off for no reason? That reason could be an overheating CPU and the computer has shut down to prevent the chip from burning out.
It might also freeze and lock up, becoming unresponsive to the mouse until you switch the power off and boot back up.
Another action that could be taken when the CPU overheats is to lower the clock speed. This has the effect of slowing down the computer and at lower clock speeds, processors produce less heat and so will cool down a little. Have you found that your computer slows down after it has been switched on for some time? It could be overheating and throttling back the CPU.
So how do you know if the CPU is overheating? Easy, just measure the temperature. RealTemp is a free utility that displays the temperature of the CPU. Download it, unzip it, and double click RealTemp.exe to run it. It displays other useful information besides the temperature.
The top section shows the processor model number, in this case an i7 4700M running at 3272.44 MHz and 20.5% load. The second section shows the temperature of the four processor cores. If you only have a two-core CPU then obviously you will only see two temperatures.
The temperature may look high at 64 to 74 degrees Celsius, but actually this is quite normal and is nothing to worry about. The third row, titled Distance to TJMax, is the maximum temperature the processor can cope with minus the current temperature. This figure will get smaller as the processor gets hotter. If it ever falls to zero, the processor is seriously overheating and could fail. (TJMax is the maximum temperature the CPU is designed to work at.)
A nice feature of this utility is that when it is minimised, it shows the temperature at the right side of the taskbar. This makes it easy to keep an eye on it without it taking up valuable desktop space.
The XS Bench button runs a performance test and displays a speed rating for your processor. The Settings button enables you to set an alarm that notifies you if the processor temperature rises above a certain figure.
It also enables you to enter the TJMax for your processor. To find this out, go to the Intel Ark and look up your processor. My Processor is a Core i7 4700M and looking down the specifications there is a TJunction temperature of 100 C. (TCase, TJunction, TMax are different ways of specifying the maximum temperatures - just look for the temperature in the specs.) I am not sure whether RealTemp knows the maximum temperature for every processor, so check the settings against the Intel specifications (or AMD if you have an AMD CPU) and manually enter them if it is not correct.
What you do if the temperature is too high?
One of the problems with old PCs is a build up of dust inside the case. Open a PC that is several years old and you will be amazed at the dust trapped in the CPU cooling find, the fans, on the motherboard and trapped in nooks and crannies.
Get the hose attachment of of vacuum cleaner and suck the dust out, being careful not to touch any of the components. Alternatively, get a can of compressed air and blow it out, but be careful not to freeze the components - the air coming out of the can is really cold, so don't get too close.
Laptops are a problem because they cannot easily be opened. You might be able to suck some of the dust out through vents around the side or underneath the laptop.