Graphics (Video) Card |
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| A graphics card (also called a video card or video adapter) is an expansion card that processes instructions sent by the CPU via a dedicated graphics processor. It acts like a small motherboard specifically dedicated to display. People who use their computers primarily for office work require only basic performance, but for serious graphics, video editing or gaming, a good graphics card becomes an important consideration. Some graphics cards also have TV-out, S-Video and video capture connections, although these may not be included as standard. Many graphics cards have the ability to output to two displays simultaneously. | |
IGP:Some computer manufacturers offer IGP (Integrated Graphics Platform) systems where graphics capabilities are built into the main system motherboard so that a separate, stand-alone graphics card is not necessary. While perfectly adequate for basic computing tasks, current IGP systems are not powerful enough for advanced uses and will not be able to handle today's 3D games.
Graphics Processor: Most graphics cards are based on either the Nvidia GeForce or ATi Radeon family. The technology is licensed to third party manufacturers such as Asus, Creative, Sapphire etc. New generations of GeForce and Radeon cards appear roughly every six months. The latest top-of-the range card is likely to cost around £300-£400. Mid-range cards are available at around £100-£200. These are capable of playing games well and are a good solution for the majority of PCs. Bottom of the range cards cost around £50. These will be fine for most PC tasks, but will perform poorly in graphics-intensive work.
Interface: The interface is the slot, or bus, required in your PC to run the card. There are two main types: AGP, and PCI Express (sometimes written as PCI-E or PCIe).
AGP is the older standard which is now becoming obsolete. However, it is still supported by some manufacturers and there is a strong second-hand market for AGP cards.
The current standard is PCI Express, which is much more powerful than an AGP card. Additional numbers relate to the throughput data that the card can handle, e.g. 4X, 8X or 16x. An AGP 2X card equates to 533MBps (megabytes per second), while 4X is 1.07GBps (gigabytes per second). AGP 8X is the current standard. If you are installing a new card, you will need to ensure that your motherboard supports throughput at that speed, or else the card's full potential will be wasted.
The old PCI slot is now obsolete and a PCI-based graphics card is likely to be found only in older computers. However, this type of card is still adequate for basic office tasks.
Memory : Graphics cards use their own dedicated memory. As with system RAM, the more memory the card has, the better the performance will be. A card with 64MB is adequate for basic office tasks, but at least 256MB is required for the latest games and video applications. Graphics card memory cannot usually be upgraded later.
IGP systems, with graphics chips integrated on the motherboard (see above), often use a portion of system RAM to display graphics, which may reduce the computer's overall performance.
Clock Speed : Manufacturers often quote megahertz (MHz) numbers. There are usually three clock speeds quoted: the core clock speed, the memory clock speed and the Ramdac clock speed. Core clock speed refers to the internal speed of the graphics processor. Memory speed (or memory clock) refers to the speed of data transfer between the card's onboard memory and the graphics processor. A clock speed of around 500MHz or greater is best for 3D graphics and games.
Ramdac speed refers to the capabilities of the digital-to-analogue converter that provides the graphics output from the card. It doesn't directly affect graphics performance but governs the range of refresh rates the card can support at a particular screen resolution. Ensure that the card you buy can display the resolutions you want to use with at least a 75Hz monitor refresh rate to avoid eye strain from screen flicker.
Overclocking : Running a graphics processor faster than the manufacturer's specified speed is popular among PC tweakers and dedicated gamers. Although this carries risks such as overheating, it can be a viable way to gain extra performance from a card when done within safety limits specified by the manufacturer. Some manufacturers sell cards that have already been overclocked, others bundle overclocking software with cards. Be sure to read the manufacturer's recommendations and instructions before overclocking.
Drivers and software : The latest driver can make a big difference to a card's performance. Visit the manufacturer's website regularly to check for updates. Other software bundled with graphics cards can include games that show off the card's performance, DVD players and graphical demos. These deals vary greatly, so check out the bundle that suits you best.
Power Supply Unit : A high-end graphics card requires a strong power supply unit (PSU) in a PC in order to function properly. It may also need a direct connection to the PSU if the graphics card cannot draw enough power from the motherboard alone. Without it, the card will simply not run.
Power demands should be researched in advance of upgrading to a more powerful graphics card. Find out from your retailer of choice just how much power your card will need, and whether it will need an extra connector. If so, what type? Make sure that your existing PSU can support it, otherwise you may have to budget for a new power supply unit as well.
Sound Cards |
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| Most PCs come with some form of sound capability built-in on the motherboard. However, there are advantages to upgrading to a dedicated soundcard. As well as achieving better sound quality, a dedicated soundcard can boost your PC's overall performance because it deals separately with sound, thus saving system resources. | |
All entry-level soundcards support 16-bit quality sound which is recorded or played back at 44.1 KHz. This is CD-quality sound and is adequate for making and playing CDs and MP3s, and for reproducing most surround sound formats on DVDs and games.
Games enthusiasts may want 3D sound support. DirectSound 3D allows sounds to pan around the speakers; Sensaura, Aureal and EAX technologies are even more convincing for games compatible with these systems.
If you intend to create your own music on your PC, you will want 24-bit sound with sampling rates of 48KHz or 96KHz. A 24-bit card will also support the newer sound formats for DVD movies, such as THX surround or Dolby Digital EX 7.1.
Entry level 16-bit soundcards can cost as little at £15, but cards by the bigger manufacturers such as Creative or Terratec start at around £25. Soundcards are usually installed in an internal PCI slot, but external USB cards are becoming popular, particularly for notebook computers. Currently, external cards are more expensive than internal cards at around £35 for an entry-level card and £60-80 for a 24-bit USB card.
Standard connectivity options should include microphone in, line in/line out for front and rear speakers, midi/joystick port, CD-in and headphone connectors. The latest cards may also feature high-speed FireWire ports for connecting digital camcorders and advanced audio options.
