| A video card, (also referred to as a graphics | | | | not be confused with the long outdated PCI format, |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