Free Tech Support - Computer Questions and Answers - Ask Bob Rankin Your Computer's Enemy Number One If your PC or Mac shuts down without warning at random times, there are several possible causes, but overheating is the most likely, and easiest to solve. Read on to learn why heat is your computer's worst enemy, and how to keep your computer from being damaged by overheating... Signs of Overheating - And What To Do Electronic components in your computer and other devices generate heat. The harder they work, the more heat they generate. But heat is the mortal enemy of all things electronic. So it's important to be alert to temperature spikes in your computer, and take steps to cool it down when necessary. How can you tell if your computer is overheating, and what can you do to keep it from frying like an egg? Sudden, inexplicable shutdowns of your computer are often due to overheating. Other symptoms of overheating include declining performance after running processor-intensive tasks for several minutes or hours. Games may run sluggishly, video may skip, and response to mouse clicks may be delayed. More alarming are sudden software crashes, random reboots, and the dreaded Blue Screen of Death. These symptoms may have multiple causes, but overheating is one suspect that needs to be confirmed or eliminated. The computer's BIOS (Basic Input/Output System) detects when the CPU, motherboard, hard drive, or graphics adapter is approaching its maximum operating temperature and shuts things down to avoid damaging that vital and expensive part. If you are experiencing shutdowns, measure your computer's temperatures and do something to lower them immediately. Temperature sensors are built into many computer components; the trick is accessing these sensors to read temperatures. Unfortunately, Microsoft Windows and Mac OS X do not have built-in utilities to let users read temperatures. You have to find third-party software. Fortunately, there are several free temperature-monitoring utilities. Some can not only monitor temperatures but also do something to lower them. SpeedFAN is a long-standing favorite temperature monitoring utility. It also monitors voltages in various devices and the speed of the fan(s) which cool your CPU, power supply, and other components. Some motherboards allow users to control fan speeds while others do not; if fan speed can be controlled, SpeedFan will do it automatically to optimize the fan's cooling. NOTE: Unfortunately, the download link on the SpeedFan website is hard to find. Be sure to click the Download link near the top of the page (next to Screenshots). On the next page, look for "The latest version is..." You'll find the download link there. Another tool to display temperature readings is Speccy. In addition to that, Speccy also gives you detailed information on every hardware component inside your Windows computer. Open Hardware Monitor is a free system monitoring program for Windows and Linux computers. It monitors all of the voltage, temperature, fan speeds and other sensors built into your motherboard, including CPU temperature. Hardware Monitor is a similar utility for Mac computers. It's part of a suite of Mac monitoring utilities written by Marcel Bresink, and it's available on a free trial basis. If you like the software and want to keep it, you can purchase it for under $10 USD. CoreTemp is designed for Intel and AMD multi-core CPUs. It can monitor the temperature in each core in each processor in your system. It also has a logging feature to record temperatures over variable periods of time. If you use a fan-speed controller that works with your system, it will provide several benefits. First, it will keep the temperature of your CPU and other components under the critical level, protecting your hardware and preventing shutdowns. Second, it will extend the life of your fan by running it only when it's really needed. Third, it will minimize that irritating noise than cooling fans often make. Other Overheating Solutions A good rule of thumb is to make sure your CPU temperature is under 70 degrees Celsius, but each processor has a different safe operating range. I recommend that you see my article What's Going On Inside My PC? to find out what hardware is under the hood, and then search for information on the maximum safe temperatures. If adjusting the fan speed doesn't bring the problem under control, there are several other possible causes for overheating. Dust is a common cause of overheating. You can buy cans of compressed air to clean the dust out of heat sinks, fans and airflow vents. Crack open the system unit every few months and you'll be surprised at how much dust accumulates there, and how it affects your system temps. Adequate air flow is important. A tower system should be placed so that its vents are not blocked by desk, wall, or other obstructions. A laptop can be elevated on a cooling pad to allow air to circulate under the machine. (In addition to cooling the laptop, this can keep human "components" from overheating as well.) It's possible that the fans themselves may need to be replaced. If a fan is noisy, that's a sign that it's not working properly. Some components have built-in fans that can fail. This recently happened to the graphics adapter on my desktop machine. My computer was shutting down unexpectedly, and SpeedFan revealed that the temperature of that component was hitting 120 Celsius (about 250 degrees Fahrenheit). After opening the system unit case, I saw that the fan attached to the graphics card wasn't spinning. As a temporary workaround, I left the case open and cooled things down with a small clip-on electric fan, until I was able to replace the graphics card. It could also be that the thermal seal between the CPU and the heat sink (which draws heat away) is not good. You can remove the heat sink and reapply thermal grease, but that's beyond the scope of this article. You can find YouTube tutorials on how to do that.