CPU Temperature Monitoring

How to Monitor Your CPU Temperature

The CPU (central processing unit) is the "brain" of your computer. And modern CPUs, despite all their energy-conserving technology, generate tremendous amounts of waste heat. That tends to happen when you pack more and more circuits into an ever shrinking electronic package. But excessive heat damages electronic components, and can sometimes cause your computer to shut down abruptly in order to prevent damage to the CPU.

That is why CPU temperature monitoring is so important. If you know your CPU is generating too much heat, you can take steps to mitigate the problem before it damages your CPU or other components irrevocably.

A CPU in "normal" use will reach temperatures from 40-100 degrees Celsius. That's not a problem if the heat is dissipated properly by a heat sink and fans. But under extremely heavy processing loads, or if the heat-dissipating systems are not working properly, a CPU can get hot enough to damage not only itself but other nearby electronic components. In cases where the cooling system malfunctions, the CPU can reach 300 degrees Celsius (572 Fahrenheit) and will literally go up in smoke.

Gaming, video editing and other CPU intensive activities can put enormous demands on a CPU. In particular, the common practice of "overclocking" kicks the CPU's operating frequency up above that for which the chip was designed. Gamers are particularly concerned with CPU temperature monitoring, but anyone who puts a heavy load on the CPU for long periods of time should also watch the temperature.

Temperature sensors are built into CPU chips and various places on motherboards. Software can access these sensors and translate their data readings into temperature readings for humans. Similar sensors monitor fan speeds, and most CPU temperature monitoring software also monitors fan speeds. The best CPU temperature monitoring software lets you control fans, CPU utilization, and other system functions that can help keep things cool.

Free Temperature Monitoring Software

Motherboard Monitor (MBM) can sense temperatures from sensors embedded in your CPU, graphics card, hard drive, and motherboard. It supports a wide range of CPU and motherboard models. But it doesn't let you adjust fan speeds. MBM is free, but has not been updated since 2008, so support for Windows 7 and 64-bit systems is a bit iffy.

My favorite CPU temperature monitoring software is SpeedFan, because it works on all versions of Windows, and also gives you fan speed control. It monitors voltage levels in various components and the status of your hard drive. SpeedFan can be configured to boost fan speed when CPU temperature reaches a specified level; keep the fan spinning all the time; and much more. Its auto-discovery and configuration modes allow SpeedFan to work with almost any combination of hardware and turn on sensors it discovers all by itself.

If you have a Mac, there's a Temperature Monitor Widget that will display all temperature sensor readings on your Mac OS X desktop.

So how hot is too hot? It depends on your specific processor. Check the manufacturer's website, or search the web to find the normal and maximum CPU temps for your model. Here's a list of maximum CPU temps that covers quite a few models.
A rule of thumb I use is to start worrying if the CPU temp is above 60 degrees Celsius.

If your CPU temperature is dangerously high during normal use, there are several steps you can take to cool things down, in addition to using monitoring software that can regulate temperatures:

• Heat sink "grease" is a highly heat-conductive, silver-based compound that carries heat from your CPU to the heat sink very efficiently. A fresh, thin layer between the CPU and the heat sink can ensure that the maximum heat transfer takes place.
• Clean your heat sink periodically to prevent buildup of insulating dust. A can of compressed air may suffice, but sometimes it's necessary to get in between the blades with toothbrush or an alcohol-moistened cotton swab.
• A bigger, better heat sink may be in order. Be careful to match your motherboard and processor to the heat sink you buy, to get the proper fit. Heat sinks with fans mounted atop them are best.
• Fans slow down with age. Depending on the design of your fan, it may be possible to lubricate it with a drop of thin oil to keep it spinning at optimal rpms. Replacement fans are inexpensive.

A few years ago, I had a computer with a small footprint desktop-style case. I guessed it was running hot, just by putting my hand near the exhaust fan. The SpeedFan software confirmed that, so I cleaned the dust out of the CPU heat sink and the temperature dropped by 20C. This computer must have had a poor ventilation system, because every month or so, the CPU temperature would creep back up to a dangerous level, requiring me to shut down and clean the heat sink with compressed air and a toothbrush.

A word of caution: Don't ever touch any of the components inside your computer while it's running. A CPU running at 100C is almost 212 degrees Fahrenheit, which is hot enough to boil water, or cause a nasty burn. Turn your computer off, disconnect it from the wall socket, and let it cool down before poking around near the CPU or heat sink.

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