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| adapter and numerous other terms), is an | | | | confused with the long outdated PCI |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