| A video card, (also referred to as a graphics | | | | leading to increased performance on the high |
| accelerator card, display adapter and | | | | end cards. PCI Express may be up to twice the |
| numerous other terms), is an item of personal | | | | speed of the AGP interface. PCI Express, aka |
| computer hardware whose function is to | | | | PCIe, should not be confused with the long |
| generate and output images to a display. The | | | | outdated PCI format, which predates even AGP. |
| term is usually used to refer to a separate, | | | | |
| dedicated expansion card that is plugged into | | | | The most powerful class of GPUs typically |
| a slot on the computer's motherboard, as | | | | interface with the motherboard by means of an |
| opposed to a graphics controller integrated | | | | expansion slot such as PCI Express Graphics |
| into the motherboard chipset. | | | | (PEG) or Accelerated Graphics Port (AGP) and |
| | | | can usually be replaced or upgraded with |
| Hardware | | | | relative ease, assuming the motherboard is |
| | | | capable of supporting the upgrade. However, a |
| A video card consists of a printed circuit | | | | dedicated GPU is not necessarily removable, |
| board on which the components are mounted. | | | | nor does it necessarily interface with the |
| These include: | | | | motherboard in a standard fashion. The term |
| | | | "dedicated" refers to the fact that dedicated |
| Graphics processing unit (GPU) | | | | graphics cards have RAM that is dedicated to |
| | | | the card's use, not to the fact that most |
| The GPU is a microprocessor dedicated to | | | | dedicated GPUs are removable. Dedicated GPUs |
| manipulating and rendering graphics according | | | | for portable computers are most commonly |
| to the instructions received from the | | | | interfaced through a non-standard and often |
| computer's operating system and the software | | | | proprietary slot due to size and weight |
| being used. At their simplest level, GPUs | | | | constraints. Such ports may still be |
| include functions for manipulating | | | | considered AGP or PCI Express, even if they |
| two-dimensional graphics, such as blitting. | | | | are not physically interchangeable with their |
| Modern and more advanced GPUs also include | | | | counterparts. |
| functions for generating and manipulating | | | | |
| three-dimensional graphics elements, | | | | Integrated Graphics Solutions |
| rendering objects with shading, lighting, | | | | |
| texture mapping and other visual effects. | | | | Integrated graphics solutions, or shared |
| | | | graphics solutions are graphics processors |
| Video memory | | | | that utilize a portion of a computer's system |
| | | | RAM rather than dedicated graphics memory. |
| Unlike integrated video controllers, which | | | | Such solutions are typically far less |
| usually share memory with the rest of the | | | | expensive to implement in comparison to |
| computer, most video cards have their own | | | | dedicated graphics solutions, but at a |
| separate onboard memory, referred to as video | | | | trade-off of being far less capable and are |
| RAM (VRAM). VRAM is used to store the display | | | | generally considered unfit to play modern |
| image, as well as textures, buffers (the | | | | games as well as run graphically intensive |
| Z-buffer necessary for rendering 3D graphics, | | | | programs such as Adobe Flash. Modern desktop |
| for example) and other elements. VRAM | | | | motherboards often include an integrated |
| typically runs at higher speeds than desktop | | | | graphics solution and have expansion slots |
| RAM. For the most part, current graphics | | | | available to add a dedicated graphics card |
| cards use GDDR3 or GDDR4 although DDR, DDR2 | | | | later. |
| or any other technology may be used. | | | | |
| | | | As a GPU is extremely memory intensive, an |
| Video BIOS | | | | integrated solution finds itself competing |
| | | | for the already slow system RAM with the CPU |
| The video BIOS or firmware chip is a chip | | | | as it has no dedicated video memory. System |
| that contains the basic program that governs | | | | RAM may be 2 GB/s to 8 GB/s, yet dedicated |
| the video card's operations and provides the | | | | GPUs enjoy between 10 GB/s and 88 GB/s of |
| instructions that allow the computer and | | | | bandwidth depending on the model. |
| software to interface with the card. It | | | | |
| contains information on the memory timing, | | | | Hybrid Solutions |
| operating speeds and voltages of the | | | | |
| processor and ram and other information. It | | | | This newer class of GPU's competes with |
| is possible to re-flash a bios although this | | | | integrated graphics in the low-end PC and |
| is typically only done by video card | | | | notebook markets. The most common |
| overclockers. | | | | implementations of this are ATi's HyperMemory |
| | | | and nVidia's TurboCache. Hybrid graphics |
| PCI Express | | | | cards are somewhat more expensive than |
| | | | integrated graphics, but much less expensive |
| PCI Express is the newest slot that most new | | | | than dedicated graphics cards. These also |
| cards fit into. It comes in a variety of | | | | share memory with the system memory, but have |
| speeds which vary in size proportionate to | | | | a smaller amount of memory on-board than |
| the speed. The older AGP slot is still used | | | | discrete graphics cards do to make up for the |
| on legacy motherboards and low end current | | | | high latency of the system RAM. Technologies |
| motherboards, although it will eventually be | | | | within PCI Express can make this possible. |
| phased out; most cards are made in both these | | | | While these solutions are sometimes |
| formats for now. Depending on what speed | | | | advertised as having as much as 512MB of RAM, |
| interface used, PCI Express video cards may | | | | this refers to how much can be shared with |
| have a higher speed interface than AGP, | | | | the system memory. |