Introduction to Computers Video and Sound Cards

Integrated Card Overview Both sound and video cards are used to expand upon functionality typically already on the motherboard The motherboard’s video and audio cards are called onboard or integrated cards These use part of the computer’s memory and sometimes it’s processor to function Usually the cheapest and least powerful solution Good for low-stress systems, like data processing workstations Motherboard documentation can tell what onboard components are offered, or the ports on the back panel will let us know

Dedicated Video Cards Consist of a GPU, or graphics processing unit, very high-speed dedicated graphics memory, and, depending on how powerful the card is it could also include a heatsink and fans. A high-end video card will likely be the second hottest component in your computer, after the CPU Can be very expensive, ranging from $30 all the way up to $1000

Display Connectors Speed and price aren’t the only factors to consider when selecting a video card. Display connectors are very important since that will limit what can be connected to the computer Popular ports include VGA, DVI, S-Video, HDMI and display ports While adapters can be used, it’s best to match the video card port to the display device port

Display Capabilities After making sure that the card has the correct video ports, it is important to make sure that the card is powerful enough to perform the job it is intended for Some parameters to consider are: resolution (the number of pixels output to the screen) refresh rate (number of times the screen is refreshed each second) support for multiple monitors Support for Virtual Reality hardware

Graphic Card API Software will communicate to the GPU through an API, or an Application program Interface DirectX and OpenGL are two of the most common APIs for 3D graphics Because of differences in which API is used, as well as differences in driver capabilities, different graphics cards that show comparable specifications may behave drastically different in different applications, and may even have drastically different performance when paired with a different brand CPU For example: A graphics card that uses memory very efficiently could out perform a more powerful card that has more memory and a faster processor for a program that has poor memory use optimization

Dedicated Graphics Card Specific Issues While the parameters we discussed so far affect both integrated and dedicated graphics cards, there are two factors to consider that only apply to dedicated graphics card Bus Type You need to make sure that the motherboard has the right expansion bus type for the card. Most dedicated video cards use PCIe x16, but depending on the make and model, PCI or PCIe X1 could be used Multi-GPU Support Some video cards have the capability to link together identical video cards to share the graphical processing load. This is very expensive and typically only done to support high end video processing, running multiple high end programs at once, or to support a large number of multiple monitors

Making Sure the Rest of the Computer is Compatible After making sure that the motherboard and graphics card match, there are still system requirements to match You have to make sure that your computer has a compatible operating system, and in higher end cards, enough ram For higher end graphics cards you’ll have to make sure your power supply has the correct connections and is outputting enough watts. High end graphics cards can put a lot of strain on weaker power supplies. Weaker graphics cards will simply accept the power coming from the PCI port

Selecting the Correct Graphics Card When selecting a graphics card to run specialized software such as games or image/video editing software, use minimum and recommended system requirements to determine an appropriate graphics card Be careful of bottlenecks! Just because your graphics card is powerful enough, you may not be able to run the software without the correct operating system, enough RAM or a powerful enough processor

Specialized Graphics Card Abilities Aside from adding specialized graphics processing, there are other capabilities that graphics cards can provide TV tuners can allow your computer to accept TV Input to watch and record live TV Video capture cards allow for computers to accept video signals from a third party, such as a video game console

Audio Cards Audio cards were once a necessity for any computer that wanted to run games or output video, but modern computers only need audio cards for specialized purposes Such as Outputting 7.1 sound for use as a home theater Sound recording High quality gaming audio

Analog Audio Sound is an analog signal naturally. It is transmitted through the air in the form of sound waves caused by air vibrating This creates alternating regions of high and low pressure, which can be mapped over time like this

Digital Audio The process a computer uses to store these analog signals as digital data is called sampling How accurate this digital data matches the analog signal is called its fidelity There are two different factors to a digital signal’s fidelity: Bits per sample affect how many different values there are to approximate the value of the sounds amplitude Sample rate is how often the analog signal is sampled. The more often the sound is sampled, the larger the file but the more accurate the graph would be

Audio Compression The goal of audio compression is to retain the fidelity of the audio file while reducing its size There are many ways to do this. Most compression algorithms cause the file to lose some of its data. This is called lossy compression. Compression algorithms that maintain perfect fidelity from the original file are called lossless compression An example of lossy compression mpeg2 audio layer 3 (or MP3) can compress an audio file to 9% of its original size, whereas FLAC (free lossless audio codec) can typically only reduce the original file to 50 or 60% of its size

Choosing an Audio Card Just like choosing a video card, selecting an audio card with the proper ports is important Most audio cards will have multiple 3.5mm jacks for audio, including line in, microphone and speaker out. These will typically be color coded and have an appropriate symbol or writeout next to the port Audio cards could also have a coaxial or optical port for higher quality digital sound The number of channels an audio card supports is also important, as each distinct speaker is going to be one channel. Most cards, including integrated audio cards, will include 2 channels, while higher end cards will include support for up to 7.1 channels. 7 speakers and a subwoofer on an LFE channel (Low Frequency Effect)

Troubleshooting Audio Devices Like any other troubleshooting, go from least invasive to most First, check that the sound is un-muted and the volume is raised, both at the software level and at the hardware level Make sure that the speakers are connected to the correct port on the computer and, if necessary, plugged into the power strip If these steps do not work, then it is time for more advanced troubleshooting Use playback devices from the sound applet to see if the correct audio device is chosen and enabled Use the device manager to see if the hardware is detected and configured appropriately If only certain audio sources won’t play, like certain videos or sound files, then make sure that the correct codec (compressor-decompressor) is installed