Computer Graphics Prof. Muhammad Saeed
Hardware II Computer Graphics Hardware ( Graphic Cards ) II
Hardware II Computer Graphics PCI(Peripheral Component Interface) With a PCI-based graphics card, every texture map has to be stored twice. First, the texture map is loaded from the hard drive to the system memory (RAM) until it has to be used. Once it is needed, it is pulled from memory and sent to the CPU to be processed. Once processed, it is sent through the PCI bus to the graphics card, where it is stored again in the card's framebuffer. All of this storing and sending between the system and the card is very draining to the overall performance of the computer.
Hardware II Computer Graphics AGP( Accelerated Graphics Port) Card AGP is built on the idea of improving the ways that PCI transports data to the CPU. Intel achieved this by addressing all of the areas where PCI transfers were causing data bottlenecks in the system. By clearing the traffic jams of data, AGP increases the speed at which machines can render graphics while using the system's resources more efficiently to reduce overall drag. It achieves the goal by:
Hardware II Computer Graphics • 1. Dedicated Port • There are no other devices connected to the AGP other than the graphics card. With a dedicated path to the CPU, the graphics card can always operate at the maximum capacity of the connection. • 2. Pipelining • This method of data organization allows the graphics card to receive and respond to multiple packets of data in a single request. Here's a simplified example of this: • With AGP, the graphics card can receive a request for all of the information needed to render a particular image and send it out all at once. With PCI, the graphics card would receive information on the height of the image and wait... then the length of the image, and wait... then the width of the image, and wait... combine the data, and then send it out.
Hardware II Computer Graphics 3. Sideband addressing Like a letter, all requests and information sent from one part of your computer to the next must have an address containing "To" and "From." The problem with PCI is that this "To" and "From" information is sent with the working data all together in one packet. This is the equivalent of including an address card inside the envelope when you send a letter to a friend: Now the post office has to open the envelope to see the address in order to know where to send it. This takes up the post office's time. In addition, the address card itself takes up room in the envelope, reducing the total amount of stuff you can send to your friend. With sideband addressing, the AGP issues eight additional lines on the data packet just for addressing. This puts the address on the outside of the envelope, so to speak, freeing up the total bandwidth of the data path used to transfer information back and forth. In addition, it unclogs system resources that were previously used to open the packet to read the addresses.
Hardware II Computer Graphics AGP: Saves RAMAGP improves the process of storing texture maps by allowing the Operating System to designate RAM for use by the graphics card on the fly. This type of memory is called AGP memory or non-local video memory. Using the much more abundant and faster RAM used by the operating system to store texture maps reduces the number of maps that have to be stored on the graphics card's memory. In addition, the size of the texture map your computer is capable of processing is no longer limited to the amount of RAM on the graphics card.
Hardware II Computer Graphics GART AGP saves RAM is by only storing texture maps once. It does this with a little trickery. This trickery takes the form of a chipset called the Graphics Address Remapping Table (GART). GART takes the portion of the system memory that the AGP borrows to store texture maps for the graphics card and re-addresses it. The new address provided by GART makes the CPU think that the texture map is being stored in the card's frame buffer. GART may be putting bits and pieces of the map all over the system RAM; but when the CPU needs it, as far as it's concerned the texture map is right where it should be.
Hardware II Computer Graphics PCI (Peripheral Component Interconnect ) Express Card PCI Express is a serial connection that operates more like a network than a bus. Instead of one bus that handles data from multiple sources, PCI-e has a switch that controls several point-to-point serial connections. These connections fan out from the switch, leading directly to the devices where the data needs to go. Every device has its own dedicated connection
Hardware II Computer Graphics PCI Express Lanes Each lane of a PCI Express connection contains two pairs of wires -- one to send and one to receive. Packets of data move across the lane at a rate of one bit per cycle. A x1 connection, the smallest PCI-e connection, has one lane made up of four wires. It carries one bit per cycle in each direction. A x2 link contains eight wires and transmits two bits at once, a x4 link transmits four bits, and so on. Other configurations are x12, x16 and x32. A x16 PCI-e connector can move 6.4 GB of data per second in each direction.
Hardware II Computer Graphics Video BIOS The video BIOS or firmware contains the basic program, which is usually hidden, that governs the video card's operations and provides the instructions that allow the computer and software to interact with the card. It may contain information on the memory timing, operating speeds and voltages of the graphics processor, RAM, and other information.
Hardware II Computer Graphics Graphics Processing Unit (GPU ) A GPU is a dedicated processor optimized for accelerating graphics. The processor is designed specifically to perform floating-point calculations, which are fundamental to 3D graphics rendering and 2D picture drawing. The main attributes of the GPU are the core clock frequency, which typically ranges from 250 MHz to 4 GHz and the number of pipelines (vertex and f ragment shaders), which translate a 3D image characterized by vertices and lines into a 2D image formed by pixels. Modern GPUs are massively parallel, and fully programmable. Their computing power is orders of magnitude greater than that of CPUs for certain kinds of operations. This has led to the emergence of general-purpose computing on graphics processing units (GPGPU). Occasionally called visual processing unit or VPU.
Hardware II Computer Graphics Compute Unified Device Architecture(CUDA) CUDA is a parallel computing architecture developed by Nvidia for graphics processing. CUDA is the computing engine in Nvidia graphics processing units (GPUs) that is accessible to software developers through variants of industry standard programming languages. CUDA gives developers access to the virtual instruction set and memory of the parallel computational elements in CUDA GPUs. Using CUDA, the latest Nvidia GPUs become accessible for computation like CPUs. Unlike CPUs however, GPUs have a parallel throughput architecture that emphasizes executing many concurrent threads slowly, rather than executing a single thread very quickly. This approach of solving general purpose problems on GPUs is known as GPGPU.
Hardware II Computer Graphics Power demand As the processing power of video cards has increased, so has their demand for electrical power. Current high-performance video cards tend to consume a great deal of power. While CPU and power supply makers have recently moved toward higher efficiency, power demands of GPUs have continued to rise, so the video card may be the biggest electricity user in a computer. Although power supplies are increasing their power too, the bottleneck is due to the PCI-Express connection, which is limited to supplying 75 Watts. Modern video cards with a power consumption over 75 Watts usually include a combination of six-pin (75W) or eight-pin (150W) sockets that connect directly to the power supply.
Hardware II Computer Graphics High-Definition Multimedia Interface (HDMI) High-Definition Multimedia Interface (HDMI) An advanced digital audio/video interconnect released in 2003 and is commonly used to connect game consoles and DVD players to a display. HDMI supports copy protection through HDCP(High-bandwidth Digital Content Protection) .
Hardware II Computer Graphics END Hardware II 16