3.12.3 Video Card Facts

Dedicated Video Cards

Are installed in an expansion slot on the motherboard Have a GPU and a dedicated, high-speed memory bank Are more powerful than integrated memory cards, but are also more expensive.

Memory

Dedicated video cards use high speed memory to store graphic data. The amount of memory on the card affects performance as well as other characteristics. The amount of memory on a card can be as low as 512 MB or as high as 16 GB Dedicated video cards use the following types of memory: DDR, DDR2, and DDR3 and similar to system memory. This type of memory is cheaper but provides less performance than special graphics memory. GDDR2, GDDR3, and GDDR5 are DDR memory specifically designed and optimized for graphical data. This memory is more expensive, but results in better performance. Integrated graphics share memory with the system.

DirectX/OpenGL

DirectX is a collection of application program interfaces (APIs) that improves graphic, animation, and multimedia creations. DirectX includes multiple components targeted to a different aspect of multimedia. For example, Direct3D is the 3D rendering component of DirectX. Applications are written using features included in specific DirectX versions. To view content written to a specific DirectX version, your video card must also support that (or a higher) version. OpenGL is an alternative standard to DirectX that is used by some applications. Most video cards support both DirectX and OpenGL.

High-bandwidth Digital Content Protection (HDCP)

HDCP is a method for protecting digital media. The purpose of HDCP is to prevent the interception and copying of protected data streams as they are sent back from a playback device to a display device (Ex: From a DVD player to an HDTV). When playing protected content from a PC, the DVD player, video card, and display must all support HDCP. If you plan on watching protected content on your PC, or playing content from your PC to an external TV, make sure the video card supports HDCP.

HDMI audio

HDMI cables are able to carry both video and audio signals: however, must video cards only send a video signal. The following techniques can be used to send an audio signal through the video card: With audio pass-through, an audio output cable is connected to the video card. The video card combines the audio signal with the video signal for HDMI output. This option is often called HDTV out. A graphics card with an onboard audio processor can decode and process audio and send it out the HDMI port. This option is often referred to as onboard sound.

Integrated video cards

Integrate the GPU with another hardware component (motherboard or CPU) Share system memory for graphic processing (So if you have 4GB with an integrated GPU you do not really have 4 GB for your system because the integrated GPU takes some of that RAM.) Are much cheaper than dedicated video cards, but are also less powerful

Multi-GPU

Some video cards can be linked together and share the graphics processing load between the two GPUs. Multi-GPU configurations are manufactured specific: NVIDIA uses SLI (Scalable Link Interface) AMD uses CrossFire Video cards are linked using a special bridge clip or through software (depending on implementation) The motherboard and each video card must use the same connection method (CrossFire or SLI). The motherboard must also have multiple PCIe x16 slots. In most cases, the video cards must be identical.

TV input/output

Some video cards include features that allow them to receive video signals and output them to a TV source. You can display the computer screen on a TV using: Analog TVs use an S-video port for video input Digital TVs use the HDMI port for input Some TVs have a VGA or DVI input. A TV tuner allows your video card to accept a cable TV input and change channels from within the computer. TV tuners can process one or more of the following signals: NTSC, PAL and SECAM are analog TV signals. ATSC signals are digital TV signals. When purchasing a new TV tuner, make sure it supports ATSC. Most TV tuners use an S-video, F-type, or RCA composite for video input

Processing capabilities

The graphics processing unit (GPU) handles all video rendering tasks. GPUs are much more efficient at processing graphic data than a traditional CPU. Using GPU to render graphics is often referred to as hardware acceleration Settings in the OS can be used to control how much video processing is offloaded to the GPU. GPUs have a clock speed that is rated in MHz. A higher speed means better performance.

Display quality

The quality of images and animations is determined by both the video card and the external display. When selecting a video card consider: Resolution: Resolution is the number of pixels displayed on screen. A higher resolution means that more information can be shown on the screen. A video card is rated by its max resolution (native resolution), which the highest possible resolution it can display. ( 1920 x 1080, or 4096 x 2160). Refresh rate: The refresh rate is the number of times in one second that the GPU draws a frame. Refresh rates are measured in hertz. A refresh rate of 70 Hz or lower may cause eye fatigue. An optimal refresh rate is between 75 Hz and 85 Hz. For best performance, select a display that matches the video card specs, and vice versa.

Display connectors

Video cards have one or more connectors for attaching an external display. Always select a video card with connector that match your display. VGA monitors use a VGA (DB-15) connector LCD and LED monitors use one (or more) of the following connectors: DVI-Integrated (DVI-I) connector HDMI connector (also used by HDTVs) DisplayPort connector Some video cards have dual head and can output to two different monitors.

Bus type

Video cards must be compatible with the expansion slots on the motherboard. Common slot types used by video cards include: PCIe x16 PCI AGP and VESA (old ass video cards)