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Why Computers Generate Heat

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One of the most common questions any computer manufacturer receives from customers is "Why does my notebook computer generate so much heat?"
Heat is a normal by-product of computer operation. Depending on the model of a particular computer, heat output can vary. For instance, a high performance computer generates considerably more heat than a lower performance computer. This is normal.
Under typical operating conditions, heat output from your computer should not be a cause for concern. In fact, heat output is generally a sign that the computer is operating as safely and as efficiently as possible. If the computer cannot disburse its heat, it may overheat and develop problems.
It is normal for a high performance computer to feel warm to the touch due to the high-performance processor and graphics capabilities. For instance, the HP ENVY computers are designed with multiple high-performance processors, advanced graphics, and a durable magnesium chassis. This durable form factor transfers heat more efficiently.

What parts in the computer generate heat?

All computers require electricity to function, and some computer components require more electricity than others. As electricity passes across circuits and through wires, it meets a natural degree of resistance. This resistance, like the friction of two hands rapidly rubbing together, creates heat. Some components, like LED lights, only require a small amount of electricity to function and their heat output is negligible. Other components, the Central Processing Unit (CPU) and Graphics Processing Unit (GPU), require considerably more electrical input. Moreover, the amount of electricity used by those components is highly variable, depending on the kind and number of applications running or calculations being performed. These operations can generate a noticeable amount of heat.
The following components generate the most heat in a computer:
  • CPU - The Central Processing Unit (CPU) generally handles processes that are not graphics intensive, such as number crunching data in a spreadsheet program or handling text input in a word processor. (Some computers may also use their CPUs for graphics operations, although with less efficiency than those having a dedicated GPU). Every calculation and instruction requires electrical input.
  • GPU - The Graphics Processing Unit (GPU) generally handles processes that are graphics intensive. (Not all computers have a GPU). Graphics, especially 3D renderings like those found in industrial design software and video games, often require different types of calculations and instructions than can typically be handled by a CPU. Graphics operations are often handled by a dedicated graphics processor. As with the CPU, a GPU handles billions of calculations and instructions per second. Depending on the kind of program being run, the GPU has the potential to produce more heat than the CPU.
  • Heat Sink - A heat sink is a thermally conductive device placed over a CPU or a GPU to absorb some of the heat that is being generated. Faster processors, as well as multi-core processors, require bigger and more elaborate heat sinks to keep their temperatures within acceptable levels. Once the heat is absorbed, it is dispersed in a controlled manner, either throughout the computer chassis or toward the cooling fans. In many cases, the fans are actually integrated into the heat sinks.
  • HDD - The hard disk drive (HDD) contains small discs that spin as information is written and accessed by other components. When there is not a lot of disk activity, the HDD puts itself into a suspended state that does not require a lot of electricity. However, when data intensive operations, such as copying files to and from the HDD, or ripping music from CD to the HDD are performed, a steady flow of electricity is needed to keep the discs spinning and this generates heat.
  • ODD - The optical disc drive (ODD) can play CDs and/or DVDs. Like an HDD, the optical disc drive spins the disc so data can be read and written. Unlike an HDD which uses magnets to read and write data, an optical disc drive uses a laser. Both the spinning and the laser require a large electrical input, and both can potentially generate considerable heat.

How is heat removed from the computer?

As heat from the various hardware components builds up, it must be dispersed or the components might overheat.
For a desktop computer, the heat-generating components are contained in a large chassis that is placed away from you (perhaps under or beside your desk) and a fan blows the heat out the vents on the back so you may not be aware of the heat generated. But for a notebook, you will likely notice the heat because you are physically closer to all the heat-generating components and vents.
This heat dispersal is not haphazard. All HP products are designed to maximize your safety and comfort when used in normal operating environments. HP has fully tested the surface temperature of its notebooks, and they are below the industry specification for surface temperature limits defined by the International Standard for Safety of Information Technology Equipment, which is also known as IEC 60950. Information about IEC 60950 is available at www.iec.ch .
The heat transferred to the chassis of the notebook, while noticeable, is not a safety issue. HP takes all potential safety matters and concerns seriously and maintains a dedicated team to promptly address them if they occur.
Heat is safely dispersed from your computer in the following ways:
  • Material - The material used for the computer's chassis plays a significant role in heat dispersal and allows heat to pass through it. Lower performance computers that generate less heat may use materials that are less permeable to heat, such as certain types of plastic. When working on such a computer, you may not notice the heat output. Higher performance computers, on the other hand, may use materials that are highly permeable to heat, such as certain polymers or metals. These materials are used to help in dispersing the heat generated. When performing processor-intensive tasks on such a computer, you may notice the heat output.
  • Design - The size and shape of a computer's chassis, not just the type of material used, also affect how heat is dispersed. There is a minimum amount of free space inside the notebook chassis. Fans are required to draw the cooling air across the heat generating components and through carefully designed channels. As computers become increasingly thinner and smaller, more subtle chassis designs to used manage air flow and heat dispersal. Generally speaking, a higher performance computer will need more space for heat dispersal in comparison to a lower performance model. A high performance computer that is too small cannot effectively disperse the heat it generates or have sufficient space to place the required heat sinks and fans.
  • Fans - The fans draw in cool air from outside the chassis and blow it over the heat producing components inside. The more heat the computer generates, the more rapidly the fans must spin to move the required amount air to help disperse the heat. Customers sometimes comment that they can hear the fan more on a high performance notebook than they would on other notebook models.
  • Vents - The flow of air into and out of a computer is critical to dispersing heat from the various hardware components. The strategic placement of vents in the chassis can maximize the free flow of cooling air through the device. A higher performance computer may have more vents than its lower performance counterpart.

What activities generate the heat?

As discussed, the two components that generate the most heat in a computer are the CPU and the GPU. However, the type of activity being performed affects the amount of heat generated or dispersed at any given moment.
The common activities that can generate heat are:
  • Playing video games
  • Performing system maintenance
  • Ripping or burning a disc
  • Copying and pasting large or numerous files
  • Downloading or uploading files to a network
  • Watching a movie
  • Streaming movies or music from the Internet
  • Rendering video or audio data
  • Running several processor-intensive programs simultaneously
  • Running your computer as a server
  • Sharing files among multiple computers
Heat in the computer can be affected by the physical environment in which the computer is located, and even by local weather conditions (such as high humidity.)

How can you manage the heat in a computer?

Your computer's basic heat profile is determined by its hardware specifications and how you use the computer. If you find the heat output of your computer unpleasant, there are a few things you can to do to try reduce the heat slightly.
  • Unblock the vents - Inadvertently blocking the air vents by pressing them up against a cubicle wall or placing the notebook in an enclosed space, can cause a computer to heat up to higher temperatures as there is no outlet for the hot air building up inside. If you unblock the vents, the computer's temperature might decrease.
  • Place the computer on an appropriate surface - Do not place the notebook on a soft surface such as a cushion, or on your unprotected lap. Soft materials and clothing can unintentionally block the vents or prevent the computer chassis from dispersing heat as it was intended. Always place the notebook on a hard surface, such as a desk or a lap tray that allows an air flow around the computer.
  • Change your computing environment - If you are using the computer in a hot, humid environment, move it to a cooler, drier one. For example, using the computer in a room that has no air conditioner in a tropical or sub-tropical location can cause it to generate additional heat. Move the computer to an air conditioned environment to keep it cool as well as remove some of the humidity from the air.
  • Blow out the dust - It is normal, over time, for dust to accumulate inside a computer. As with blocked vents, dust inside the computer can interfere with the air flow and may impact heat dispersal. Use compressed air to clear the vents of accumulated dust. Compressed air canisters, designed specifically for use with computers are sold at many computer stores.
  • Adjust the computer's power options - Both Windows 7 and Windows Vista have power management options that allow you to set the computer's performance level. Higher performance requires more electricity, which subsequently creates more heat. You can reduce the computer's performance to reduce the power requirements which reduces the heat output slightly.
  • Adjust the CPU and GPU performance - Many CPU and GPU manufacturers have tools that can be download from their web sites to adjust processor performance. Reducing the CPU and GPU performance settings might reduce the amount of heat generated.
  • Use a cooling system - There are many types of cooling systems for high performance computers. For example, elevated notebook trays with mechanical or liquid cooling systems are available for purchase. You should never disassemble an HP computer and install an alternate cooling system. Doing so may affect your warranty coverage and can have unpredictable results that may cause irreparable damage to the computer.
  • Stop using multiple processor-intensive applications at the same time - If the heat output is really a concern, you can reduce the power requirements by using only one processor-intensive application at a time.
  • Use the HP Support Assistant to stay up-to-date - To help optimize performance, HP suggests that you download and run the HP Support Assistant to check for and install the latest BIOS version and system software. HP periodically updates critical device drivers and BIOS features that can affect a computer's heat profile. Run the HP Support Assistant frequently to ensure that your computer is not missing any important updates that may impact the amount of heat your computer generates. If you choose not to use the HP Support Assistant, you can go to the HP Support and Drivers download page to manually install updates.
Once you become accustomed to your computer's heat profile, if you notice that the computer begins generating more heat than normal, or begins behaving erratically when it heats up, turn it off immediately and contact HP Support.
WARNING:HP notebooks are optimized for international safety standards, including issues related to heat and the use of parts that are maintained and controlled by HP. Removing the specified hardware from an HP computer and replacing it with parts not issued by HP, may cause the computer to run hotter than normal.

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