PC Overheating: When Things Get Too Hot

Almost every major component on your PC is designed and manufactured with a specific operating temperature range in mind. Exceed that temperature, and you may not have the effectiveness you have within the proper heat range. Exceed that temperature regularly, and you not only invalidate the product warranty, you’re apt to kill the component, either now or later.

Of course, different devices have different heat thresholds, but many devices begin to experience difficulty once the operating temperature climbs past 150 degrees Fahrenheit. (Actually, this is often a range between 120–175 degrees, or about 50–80 degrees Centigrade). While the room where your PC is located may be a comfortable 72 degrees, inside that case the temperature can easily soar past 150 degrees.

Some estimates, including one available at PC Power and Cooling (www.pcpowerandcooling.com), a widely respected online vendor for cooling devices, report that for every 18 degrees you push a PC component past its heat threshold, you cut the life expectancy of that component by as much as half. Even if the real numbers are far lower, it could still spell an uncomfortably high amount of device failure.

While overheating has serious long-term effects for PC life and use, there are immediate short-term effects, too. An overheated PC is an unstable one, and the quality of the data written to such a system can become highly suspect. Files you think you’ve saved may not be there when you return from a quick restart. What you type at the keyboard may turn into a nonsense of jumbled characters and symbols on the screen, making you think that perhaps your keyboard has shorted.

Note 

According to PC Power and Cooling’s web site, the five hottest components within a PC are usually the CPU (always the hottest), the video adapter, the motherboard’s core-logic chipset, the installed memory, and then the hard drive(s).

What’s Making the PC Overheat

Before I list the factors that cause a PC to overheat, let me remind you that you can cut down on the occurrence of these problems by following the preventive measures described in Chapter 3, “Prevention: Limiting Your Risks.”

The following are the most common causes for PC overheating:

• Blocked intake and exhaust vents

• Operating the PC in a very warm environment

• Dirty or malfunctioning internal fans

• Heavy dust accumulation on internal components

• Overcrowding of equipment within the case

• Adding several “hot” components without augmenting internal cooling

• Overclocking (the process of changing hardware settings to “push” hardware beyond its rated speed/operation)

Symptoms of Overheating

Overheating can actually cause some rather bizarre and not-easily-explained phenomena. Here are just some of the symptoms you might see with either acute one-time or chronic overheating:

• A PC that was operating fine when you first turned it on begins to develop increasing problems. For example, you type one thing but the monitor displays another, opening or saving files to a disk gives you drive errors, or hardware “disappears.” A restart of the PC does little or no good.

• You place your hand near an exhaust point, such as at the location of the power supply fan, and notice little or no air being pushed out against your hand. Under ideal conditions, the fan output here isn’t exactly robust, but you should feel a steady flow of warm air.

• If you turn the PC on, it appears to start normally and then resets itself after a short period of time, usually the time it takes for the PC to warm up.

• You notice parts of the case, especially where drives are located or the side where the motherboard sits, become extremely warm to the touch.

• You go inside your system—with power disconnected and properly grounded—and note that components are (or almost are) too hot to touch.

• There may be a smell—often a compound of smells related to overheated components, grease, and dust—that may or may not seem like burning.

• You receive an on-screen warning about internal temperature. This is a feature with some motherboards and accessories you may add, but not available or enabled on every system.

Tips to Avoid Overheating

The best way to limit the chances of your system overheating is to follow the maintenance recommendations offered in Chapter 3:

• Keep your PC work area clean and free of dust and debris.

• Keep the PC vents free of blockage.

• Keep air circulation within the PC optimum by keeping air paths open and fans working and free of dust.

If your PC is located in a room that tends to get very warm despite drawing curtains or blinds against the sun and you have no air conditioning present, try to schedule your PC time away from the hottest time of the day. For example, I live in an area where air conditioning is rare. In the hottest times in summer, I adjust my schedule to get on the PC early in the morning and return to it later in the evening, leaving my PC turned off or in low-power mode during the mid-to-late afternoon hours. This schedule also helps me avoid the late afternoon thunderstorms that frequent our summer days.

On the flip side, it’s not good to fire up your PC when it has been sitting in a very cool or cold room, since the warming of such cold components can cause condensation and shorting. If your PC is located in a room that doesn’t get much heat until you arrive at your desk, consider turning on the heat first and allowing the temperature to slowly rise into a normal range well before you turn on the system.

You’ll find more ideas when I talk more about the ways a PC tries to cool itself and how you can augment this cooling process.

PC Air Circulation and Vents

In standard PC architecture that includes PC case design, fresh air comes in the vents located at the bottom of the PC. This air should then move towards the back of the PC case and then be drawn upward until it exits the exhaust fan vent at the top rear, like with the power supply fan. Along the way, this fresh air flows past the hot components and helps push the hot, stale air found around these components away and out of the PC.

You can prevent air blockages within your PC by keeping cable bundles grouped together and positioned out of the way and keeping vents clear. However, most PC case designs—compounded by the devices you pack into them—allow for the creation of no-breeze or so-called dead zones, areas where air simply does not move. In dead zones, heat can build to much higher temperatures than in areas where air is moving to push the hot air away from components.

Of course, there are some areas of the interior of the PC where this isn’t so critical. In other areas, like around filled drive bays containing your hard drive, CD drive, and floppy drive, or around a full row of installed PCI cards, warm-to-hot stagnant air can have troubling symptoms and sometimes dire consequences.

Depending on your situation and whether you can establish that internal overheating is a factor in your problems, augment your current in-case air circulation by adding additional PC fans, checking the status of your CPU heat sink, installing some type of heat monitor, or even changing your PC case.

Tip 

Find yourself with a fair amount of debris building up in your PC, drawn in by the intake vents? Many smart folks get thin filter material such as the type you might find in an air conditioner or air cleaner and cut it to fit the size of the intake vents. Then they affix this filter material to the inside of the vent (only on the intake vents) to help trap ash, dust, and other debris before it gets sucked into the system. Heat-safe tape applied around the edge of the filter against the case worked well for me in the days when my PC sat near a woodstove.

The Role of PC Fans

Take a good look around your PC case, and you may notice that yours may not have that much in the way of intake vents bringing air into the PC or exhaust vents located at the back of the PC. If you depended solely on these glorified holes for air circulation within your PCs, it would be like sitting your CPU under a skylight in an aluminum trailer positioned in the desert during the high sun of a summer afternoon with just little vent windows at the front and back providing any cooling.

Fans are installed to move air away from the hottest components and to force that warm air out of the PC. Most PCs include at least two fans: the power supply fan that pushes exhaust out the back of the PC and the CPU fan, both of which have been discussed in this book. Some devices that you install may have their own fans, like the one built into my ATI Radeon video adapter.

As you read, think back to the preventive environment described in Chapter 3. Internal fans can do a great job, but if the air coming into the PC from the room is overheated, you’re going to increase the temperature inside the case. You can help your PC fans—and your PC itself—by keeping the area around your PC reasonably cool. If you can’t keep it cool, limit the amount of time the PC is on when room air is very warm.

Warning 

Excessive internal heat around PC drives can actually distort and warp the drive platters that store your data.

Types of Fans Found in a PC

Besides the types of fans already mentioned, there are other fans that are not commonly installed in brand-new systems (especially budget ones) but are available for purchase separately. These include a fan that installs to one of the available slots in your motherboard, much like a sound adapter or internal modem does. This type of fan falls into the category of system or case cooler.

Other fan types include special fans designed specifically to cool drives (drive coolers) and to cool expansion cards (card coolers or graphics coolers). Both drive and card coolers are great in defined situations, where a specific device (a drive or an installed PCI card) tends to run hot or is affected by the heat being produced by something positioned close to it.

There are other specialty fans, including those with double fan assemblies, elaborate coolers, and something called a peltier cooler. A peltier cooler is a fan/heat sink combination that uses a peltier element that acts as a heat pump as it draws very hot air away from the hottest components, such as a CPU. This is ideal for the component being cooled, but a peltier cooler actually heats up the rest of the case because it’s more effective in drawing heat from its target and tends to be a power hog, too.

Note 

PC cooling specialty sites and stores offer a host of articles, tips, and step-by-step instructions on adding both system and spot-specific coolers to your system. These include PC Power and Cooling and The Heat-Sink Guide (www.heatsink-guide.com).

Checking Fan Function and Cleaning

I recommend that you check your fans for dirt and debris whenever you’re inside the PC case. Wherever possible, fans should be removed for cleaning so that you don’t end up sending the debris from the blades onto the other components inside the case.

Chapter 10, “Understanding and Troubleshooting Hardware Failures,” explains in detail how to check and clean your PC fans.

Adding Fans

Positioning of fans is critical to achieve the results you want. After all, it’s always possible that by trying to spot-cool one hot device, you may cause unintended problems for another device that becomes blocked by the effort and equipment used to cool the first device.

When adding fans, do your homework before you install them. As I mentioned in the last tip, most of the online cooling sites offer good recommendations for fan placement. They also offer step-by-step instructions for novel solutions, including how to drill a blowhole in your PC case to increase air circulation and allow another place for hot air to escape.

The Role of Heat Sinks

A heat sink is simply an aluminum alloy compound used in conjunction with a processor to draw the heat away from the processor and send that heat out into the circulating air of the PC case, where it can be pushed out through back vents.

The heat sink is affixed to the CPU through the use of a special thermal compound you can get wherever you can buy a CPU or other chips. (You may see other high-heat components such as a video adapter’s graphics processor use a heat sink as well.) If you buy a PC pre-assembled, all this is done for you. But if you have to replace the CPU later on or, as sometimes happens, the thermal compound breaks down, you must reattach the heat sink before you run the PC.

Tip 

If you have to replace a heat sink, don’t slather on the compound thinking if some is good, more is better. Cover the core with thermal compound and leave it at that.

A dirty heat sink is a less effective one. If the interior of your system tends to accumulate much dust, dirt, or ash, clean a heat sink before you attempt to re-affix it. This can be done using rubbing alcohol and a dust-free cloth; pay close attention to removing the previous application of thermal compound. Leaving bits of old compound in place when you apply the new compound may interfere with an optimal attachment.

PC Temperature Monitors

Along with fans, heat sinks, and special cooling arrangements, you can buy temperature monitors that permanently mount within your PC or hand-held probes that you can hold or place.

Such monitors can be valuable if you suspect overheating or you know that your system has had issues with overheating in the past. They are much more reliable than leaving your cover off and carefully placing your hand near an area to test heat; measuring equipment is less subjective than you are. In addition, the very act of removing the cover to test temperature makes it less accurate because you’re no longer testing the enclosed environment of a closed case; removing the cover can immediately drop the temperature several degrees.

Temperature monitors can be purchased in just about every price range (from about $20 to well beyond $100) from the same types of places, both online and locally, that sell PC fans and CPUs. Radio Shack is a good place to look for the probes themselves.

Before you shop, however, check your PC documentation and BIOS Setup to be sure you don’t already have a temperature monitor built into your motherboard. While you’re in BIOS Setup, make sure that the temperature monitor/alarm is enabled or it won’t help.

Watching What You Install

Now that you have a better grasp of the issues related to internal PC temperature and the consequences of overheating, you can appreciate why it’s important to consider the effects on temperature when you add new equipment to your system.

Obviously, the more congested with internal hardware your PC becomes, the more likelihood your system may experience heat-related problems due to increasingly limited air circulation. This doesn’t mean you must forego adding equipment. Think carefully about a device’s placement and the type of device it is because some devices will heat considerably more than others.

Certain devices are more prone to heat than others. These include:

• Large, high-speed drives

• Certain video adapters

• Certain CPUs

• Peltier coolers and other types of special targeted coolers

You also want to think about your PC case. While many users keep the same case throughout the life of a PC, you can upgrade your PC case to accommodate increasing internal hardware demands. More room coupled with a better-designed case layout may promote better air circulation and reduce overheating.

If you spend any time looking at PC cases on the Web, you’ll be amazed at the possibilities out there. Many PC cases offer not just extra room, but easier access (for example, a front panel for installing external components) and even fashion. One I saw in England offered a lava lamp effect built into the case. I’m not at all sure that will help with overheating, but it might take your mind off your slow Internet connection.

A Cautionary Tale: The Brewing Storm in the Basement

Power problems can be tough to figure out. While you might be aware that using the modem during a lightning storm can result in later hardware problems, you might not know about the other power-related problems you can face.

When I ran a busy online hardware help forum for The Microsoft Network, we had a woman who kept having hardware failures. Since she had only recently purchased her system and it was still within its warranty period, I suggested she contact her PC manufacturer to tell them she wanted a full evaluation of her system to see what might be causing the problem.

The manufacturer took the unit back, scoped it out, and found nothing wrong. But the company tried to give her good service, so they shipped her a new unit.

Within a few weeks, she was back in my help forum telling me she was having failures yet again. I asked her about storms in her area because I knew she lived in a storm-prone area of Florida where many of the utility lines are overhead and susceptible to weather-related damage.

Sure enough, she had been hit by bad storms that had been disrupting power for many weeks. Based on that, I recommended that during such storms, she turn off the PC, completely disconnect (remove the power cord, disconnect the phone line from the modem) her PC, and get a good surge protector to place between her house wiring and the PC.

She was back pretty quickly with a sudden memory failure after another storm. Yet she told me that she had the surge protector in place and had been keeping the PC disconnected during storms. But then she provided the clue I needed: her surge protector had burned out when she turned the PC back on after the storm.

I’ll spare you all the sordid details, but the culprit turned out to be bad wiring in her basement, which was on the same circuit as the room where she kept her PC. While she was disconnecting the PC during power fluctuations and storms, a huge, old freezer in her basement had problems cycling back up after a storm. So each time she turned on her PC within a half hour after the storm, the PC was being affected by spikes that the freezer was sending along the wiring.

An electrician fixed her problem for less than the cost of one of the drives she lost when the problem first began.

Sluggish PC performance ranks right up there with Windows instability and hardware failures and interferes with your ability to work and play with your PC. In Chapter 12, “PC Performance: Diagnosing, Monitoring, and Troubleshooting Problems,” I’ll show you how to monitor and troubleshoot performance-related issues.