When computers work hard, such as when playing games, video editing and other processor-intensive activities, it gets hot. Is it too hot? Monitor the temperature to prevent heat problems.

You may have noticed that the computer gets quite hot and you may be able to feel the heat through a desktop computer’s computer’s case and laptops start to burn your legs. It can be uncomfortable gaming with a laptop in your lap.

Apart from being obviously hot to touch, the most annoying problem may be the fan, which blows out hot air like a hairdryer and is often very noisy, especially in a quiet room. Is it too much to handle?

Heat build up has always been a problem with processors right from the early days of computing. 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 and a rise in temperature is not necessarily bad, 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 powered off for no reason? It could be caused by an overheating CPU and the computer has shut down to prevent the chip from burning out.

An overheating computer 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 whatever program is running 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.

Monitor CPU temp with RealTemp

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.

It does not look like the utility has been updated since 2012, but it runs on my Windows 10 PC. I haven’t tried every feature, but the temperature monitoring functions are fine. Celsius and Fahrenheit units are supported.

The top section shows the processor model number, the speed in MHz and the percentage workload.. The second section shows the temperature of the processor cores, four in this case. 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. For example, for an Intel Core i7 10th generation, looking down the specifications there is a TJunction temperature of 100 C. TCase, TJunction, TMax are different ways of specifying the maximum temperature – just look for the temperature in the specs.

RealTemp is so old it cannot know the maximum temperature for every processor, but you can look it up at the Intel website and enter it into the utility. AMD will have similar specifications and you can look up the maximum temperature manually enter it.

CPU Thermometer shows how hot the CPU got

CPU Thermometer is a more recent utility than RealTemp and the most recent version is a couple of years old. It works fine on my HP laptop running Windows 10.

The download is an executable file, but it just unzips to a folder and it can be run from there without installing it. It is simple and easy to use. It adds an icon to the right side of the Windows taskbar and right clicking it enables a Hide/Show menu to be used. It either hides or shows the main window.

It lists the temperature for each processor core, the load and power consumption. It also records the maximum values seen, so you could play a game or use some other processor intensive software then look at CPU Thermometer to see how high the temperature reached. Celsius and Fahrenheit units are supported.

There are no high temperature warnings and it is up to you to keep an eye on the values.

See CPU temps in Wise System Monitor

Wise System Monitor is a free utility that enables you to see what components are used inside the PC without needing to take it apart and see for yourself. In the sidebar are the various parts of the PC like motherboard, memory, graphic card, processor and so on. Select Processor and below the technical specifications of the part is the current temperatures of the cores and an overall average temperature.

The average is 81 Celsius in the screenshot (it should show Fahrenheit in the US), and Core 3 is running at 86 C. That is probably why the fan is blowing right now.

This utility has many more functions if you want to explore them.

Check CPU temp with HWiNFO

HWiNFO is a free utility that reads all the sensors on the motherboard and in chips and other system components. Go and get the portable version, unzip it and run either the 32-bit or 64-bit program (most people have 64-bit Windows).

It asks if you want to run it in sensor-only mode. Select it and it shows a lot of information, more than you need and it is a bit overwhelming at first. Scroll down and among the long list of sensor data are some temperatures. It shows the current, minimum, maximum and average values.

If there is too much information for you, go into the settings and you can choose what to show and what to hide.

What if the temperature is too high?

One of the problems with old PCs is a build up of dust inside the case. Open a desktop PC that is several years old and you will be amazed at the amount of dust that is trapped in the CPU cooling fins, around the fans, on the motherboard and trapped in nooks and crannies inside the case.

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 and this means that there could be a lot of dust inside the case covering the components on the motherboard and trapped in and around fans that you cannot remove.

You might be able to suck some of the dust out through vents around the side or underneath the laptop with the hose attachment on a vacuum cleaner, or blow compressed air into the vents, but it is a drawback of laptops. Old ones tend to run their fans a lot and this is simply to cope with the insulating dust coating the components inside.