Graphics Cards

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Graphics Cards

• Presentation by David Fong

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What are graphics cards used for?

• Animation
• Gaming both PC and console
• Design/Drafting
• Special effects creation/editing
• Medical Instruments
• And other purposes where fast rendering and high
  resolutions are needed

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History

• Over the years, more colors, higher resolution,
  faster bus interfaces, and more memory.

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History

• Monochrome Display Adapter (MDA) was the first
  video card created in 1981 displays green text
  on black screen
• Video Graphics Array (VGA) very popular and was
  the standard in almost every PC up until recently
• First 3d video cards were released in 1995 and
  they used SVGA learned to create 3d effects

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Monochrome Monitor
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Components

• Graphics Processing Unit (GPU) perform
  calculations for rendering and figure out what to
  do with each pixel
• Video Memory storing images and information
  about each pixel
• Output Common outputs include Video Graphics
  Array (VGA) for CRT monitors, Digital Visual
  Interface (DVI) for flat panel displays, and
  Video-in-video-out (ViVo) for television and
  video cameras

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Components

• Heat sink and Fan used to cool the GPU, just
  like the CPU of a computer having the same
  cooling instruments
• Motherboards PCI before AGP
• Motherboards Accelerated Graphics Port (AGP)
  compatible popular decade ago Peripheral
  Component Interconnect Express (PCI-E) gaining
  popularity
• BIOS chip that stores settings, information about
  each component of the graphics cards, and can be
  altered for over-clocking

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Picture of Graphics Card
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How graphics cards work?

• Take data from CPU and figure out what to do with
  each pixel to create image
• Create wire frame using vectors
• Fill remaining pixels with color, lighting, and
  texture
• The filling will consider viewpoint
• For games and video, the graphics cards has to do
  the above steps for 30 frames per second

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How graphics cards work?

• In greater detail
• GPU creates image, stores image with location and
  color of each pixel in memory
• Memory also holds completed images until its
  time to display them (frame buffer)
• Digital-to-analog converter (DAC) is connected to
  memory and translates image into analog signals
  that is sent through monitor cable and the image
  is displayed on monitor

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Wire image

• Draw 12 lines for cube, then fill in
• A curve is created by many short lines

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3d Image Development
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3d effect Mip-Mapping

• Pre-calculated images of target image
• Target image, may have several copies which is ¼
  the size of previous image
• Makes rendering faster when the output is moving
  toward and further away from a target image

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3d effect Z-buffering

• Each pixel is part of a 2d coordinate (x-y
  coordinates)
• Depth is z-coordinate
• When a new object that is rendered wants to take
  a pixel, Z-buffering checks which pixel is closer
  to the observer, the old pixel or the new pixel
  based on the z-coordinate
• If new pixel is closer, the new pixel is buffered
  and replaces old pixel

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3d effect Anti-aliasing

• When trying to represent high resolutions signal
  at lower resolutions.
• Smoothes out edges to the human eye by blending
  of colors

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Anti-aliasing
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Anti-aliasing
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Anti-aliasing
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Anti-Aliasing
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Anti-Aliasing
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Extra Features

• ATI and nVidia added enhancements to their GPUs
  including
• Anti-aliasing which makes smoother edges for 3d
  objects
• Anisotropic filtering creating crisper images
• Dual-monitor support which can increase
  productivity
• TV-tuner

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Do you need a graphics card?

• If you only surf the web, watch streaming videos,
  chat, or word processing, the integrated graphics
  processor on your motherboard is enough.
• If you play games or work with 3d graphics, then
  a graphics card is recommended.

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How to judge quality of graphics card?

• Most of the time, you can judge the quality of a
  graphics card by the processor speed and how much
  memory the card has.
• There are some sites that do benchmark tests
  (www.tomshardware.com) for comparable cards by
  running graphics intensive games or environments
  and measuring the frame rate (frames per second)
• Higher the frames per second, the smoother the
  transitions for frames in games and video

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Manufacturers

• Intel develop IGPs (integrated graphics
  processors)
• AMD (acquired ATI) develop GPUs
• Nvidia also develop GPUs
• Different manufacturers take GPUs and other
  components to assemble video cards thus creating
  slight variations of video cards with same GPUs
• Video cards are marketed with GPU manufacturers
  brand name
• Most popular video brands are the Radeon of ATI
  and GeForce of Nvidia

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IGPs vs Graphic Cards

• About 90 of computers use IGPs
• IGPs use the memory in the system instead of
  having dedicated video memory like Graphics Cards
• IGPs are way cheaper than Graphics Cards
• Performance always favors Graphics Cards
• Almost impossible to play high end games on IGPs

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How much video memory you need?

• Depends on resolution and bits per pixel (how
  many colors possible for pixel)
• 32bpp 232 4,294,967,296 colors
• Minimum memory Resolution x bpp
• Example 1024 x 768 x 32 bits per pixel
• 25,165,824 bits / (8 bits per byte)
• 3,145,728 bytes
• So need a little bit more than 3 MB of memory

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Future

• Because of growing processor speeds, there may be
  a need to develop a faster way for the CPU to
  transfer bits to the GPU (like how AGP was needed
  a decade ago, and PCI-E few years ago)
• With greater GPU speeds, comes greater demand for
  power (a simple PCI-E connection is not enough to
  power a high quality graphics cards these days,
  most likely needs additional sockets to be
  connected for power)
• The growth in processor speed and memory will
  create higher fps at greater resolutions

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Twix

• How to calculate the minimum amount of video
  memory you need?

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Twix

• What was the most popular bus interface before
  PCI-E?

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Twix

• How do most benchmark tests measure the
  performance of a graphics card?

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Sources

• Howstuffworks.com
• Wikipedia.org
• Encarta.msn.com
• Brighthub.com
• Pcwize.com