AGP Accelerated Graphics Port
An AGP slot (maroon, although the color is usually brown) and two PCI slots
Year created:	1997
Created by:	Intel
Superseded by:	PCI Express (2004)
Width:	32 bits
Number of devices:	1 device/slot
Capacity	up to 2133 MB/s
Style:	Parallel
Hotplugging?	no
External?	no

The Accelerated Graphics Port (also called Advanced Graphics Port, often shortened to AGP) is a high-speed point-to-point channel for attaching a graphics card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Between 2004 and 2007, AGP was replaced by PCI Express. As of 2007 new AGP cards and motherboards are still available to buy, however they are becoming much less common. Download high resolution version (915x547, 141 KB)AGP slot. ... This article is about the computer bus type. ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... PCI Express (formerly known as 3GIO for 3rd Generation I/O, not to be mistaken with PCI-X) is an implementation of the PCI computer bus that uses existing PCI programming concepts and communications standards, but bases it on a much faster serial communications system. ... This article is about the unit of information. ... In computing, a parallel port is an interface from a computer system where data is transferred in or out in parallel, that is, on more than one wire. ... This article is about the machine. ... A motherboard is the central or primary circuit board making up a complex electronic system, such as a modern computer. ... This article is about process of creating 3D computer graphics. ... PCI Express (formerly known as 3GIO for 3rd Generation I/O, not to be mistaken with PCI-X) is an implementation of the PCI computer bus that uses existing PCI programming concepts and communications standards, but bases it on a much faster serial communications system. ...

Advantages over PCI

As computers became increasingly graphically oriented, successive generations of graphics adapters began to push the limits of PCI, a bus with shared bandwidth. This led to the development of AGP, a "bus" dedicated to graphics adapters. This article is about the computer bus type. ... In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers and typically is controlled by device driver software. ...

For the needs of modern graphics adapters, AGP is superior to PCI because it provides a dedicated pathway between the slot and the processor rather than sharing the PCI bus, allowing for faster communication. AGP also uses sideband addressing, meaning that addressing for packets is carried outside of the packet, so the entire packet does not need to be read to get addressing information. In addition, to load a texture, a PCI graphics card must copy it from the system's RAM into the card's framebuffer, whereas an AGP card is capable of reading textures directly from system RAM using the Graphics Address Remapping Table (GART). GART reapportions main memory as needed for texture storage, allowing the graphics card to access them directly.^[1] The maximum amount of system memory available to AGP is defined as the AGP aperture. In computer hardware, a feature of the Accelerated Graphics Port (AGP). ... The framebuffer is a part of RAM in a computer allocated to hold the graphics information for one frame or picture. ... The Graphics Address Remapping Table (GART) is an I/O memory management unit used by AGP and PCI Express graphics cards, through which textures, polygon meshes and other data is loaded directly from the computers physical memory utilizing DMA. See also Agpgart Category: ... Spherical texture mapping Texture mapping is a method, pioneered by Edwin Catmull, of adding detail, surface texture, or colour to a computer-generated graphic or 3D model. ... An aperture is a portion of the computer-addressable physical address space which is associated in hardware with a particular device or memory unit. ...

The two main reasons graphics cards with the PCI interface are still produced are that, first, they can be used in nearly any PC; because while some motherboards with built-in graphics adapters lack an AGP slot, few, if any, modern desktop PCs lack PCI slots. Secondly, a user with an appropriate operating system can use several PCI graphics cards (or several PCI graphics cards in combination with one AGP card) simultaneously — to give many different video outputs (for the use of many screens). This is almost impossible with AGP 1.0 and AGP 2.0 cards, because they do not support more than one AGP Master (video card) per AGP Target (chipset interface). AGP 3.0 does support more than one AGP Master per AGP Target, but nonetheless few PC motherboards are equipped with more than one AGP slot. Some server-class computers support having multiple AGP slots in a single system: the HP AlphaServer GS1280 has up to 16 AGP slots, the AlphaServer ES80 up to 4 AGP slots, and the AlphaServer ES47 up to 2 AGP slots. An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is a very large, global company headquartered in Palo Alto, California, United States. ...

History

The AGP slot first appeared on x86 compatible system boards based on Socket 7 Pentium and Slot 1 Pentium II processors. Intel introduced AGP support with the i440LX Slot 1 chipset in mid-October 1997 and a flood of products followed from all the major system board vendors.^[2] x86 or 80x86 is the generic name of a microprocessor architecture first developed and manufactured by Intel. ... Socket 7 is a physical and electrical specification for an x86-style CPU socket on a personal computer motherboard. ... This article does not cite any references or sources. ... Slot 1 refers to the physical and electrical specification for the connector used by some of Intels microprocessors, including the Celeron, Pentium II and the Pentium III. Slot 1 was a departure from the square ZIF PGA/SPGA sockets used for the Pentium and earlier processors. ... Intel Pentium II Logo The Pentium II is an x86 architecture microprocessor by Intel, introduced on May 7, 1997. ... This is a list of computer motherboard chipsets made by Intel. ... Slot 1 refers to the physical and electrical specification for the connector used by some of Intels microprocessors, including the Celeron, Pentium II and the Pentium III. Slot 1 was a departure from the square ZIF PGA/SPGA sockets used for the Pentium and earlier processors. ...

The first Socket 7 chipsets to support AGP were the VIA Apollo VP3, SiS 5591/5592, and the ALI Aladdin V. Intel never released an AGP-equipped Socket 7 chipset. FIC demonstrated the first Socket 7 AGP system board in November 1997 as the FIC PA-2012 based on the VIA Apollo VP3 chipset, followed very quickly by the EPoX P55-VP3 also based on the VIA VP3 chipset which was first to market.^[3] VIA Technologies logo VIA Technologies is a Taiwanese manufacturer of integrated circuits, mainly motherboard chipsets, CPUs, and memory, and is part of the Formosa Plastics Group. ... Silicon Integrated Systems (SiS) is a company that manufactures, among other things, motherboards. ... This article or section is in need of attention from an expert on the subject. ... First International Computer, Inc. ...

Early video chipsets featuring AGP support included the Rendition Vérité V2200, 3dfx Voodoo Banshee, NVIDIA RIVA 128, 3Dlabs PERMEDIA 2, Intel i740, ATI Rage series, Matrox Millennium II, and S3 ViRGE GX/2. Some early AGP boards used graphics processors built around PCI and were simply bridged to AGP. This resulted in the cards benefiting little from the new bus, with the only improvement used being the 66 MHz bus clock, with its resulting doubled bandwidth over PCI, and bus exclusivity. Examples of such cards were the Voodoo Banshee, Vérité V2200, Millennium II, and S3 ViRGE GX/2. Intel's i740 was explicitly designed to exploit the new AGP feature set. In fact it was designed to texture only from AGP memory, making PCI versions of the board difficult to implement (local board RAM had to emulate AGP memory.) Rendition was a maker of 3D graphics chipsets in the mid- to late-90s. ... 3dfx Interactive was a company which specialized in the manufacturing of cutting-edge 3D graphics processing units and, later, graphics cards. ... 3dfx Interactive was a company which specialized in the manufacturing of cutting-edge 3D graphics processing units and, later, graphics cards. ... NVIDIA Corporation (NASDAQ: NVDA) (pronounced IPA: ) is a U.S. corporation specializing in the manufacture of graphics processor technologies for workstations, desktop computers, and handhelds. ... Released in late 1997 by NVIDIA, the RIVA 128, or NV3, was one of the first generation of integrated consumer 3D chips. ... 3Dlabs is a graphics card vendor that develops high-end graphics chip technology and markets its Wildcat computer graphics solutions to design professionals in the CAD and content creation industries. ... The Intel740 was a graphics accelerator chipset made by Intel. ... The ATI Rage is a series of graphics chipsets offering 2D GUI acceleration, video acceleration, and 3D acceleration. ... Matrox Electronic Systems Ltd is a Canadian company based in Dorval, Quebec, which produces video card components and equipment for personal computers. ... The Virtual Reality Graphics Engine (ViRGE) graphics chipset was one of the first 2D/3D accelerators designed for the mass market. ...

Microsoft first introduced AGP support into Windows 95 OEM Service Release 2 (OSR2 version 1111 or 950B) via the USB SUPPLEMENT to OSR2 patch.^[4] After applying the patch the Windows 95 system became Windows 95 version 4.00.950 B. The first Windows NT-based operating system to receive AGP support was Windows NT 4.0 with service pack 3, introduced in 1997. Linux support for AGP enhanced fast data transfers was first added in 1999 with the implementation of the AGPgart kernel module. Windows 95 is a consumer-oriented graphical user interface-based operating system. ... Windows NT 4. ... A Service Pack (more commonly, SP) is a software program that corrects known bugs, problems, or adds new features. ... This article is about operating systems that use the Linux kernel. ... AGPgart is a kernel module for Linux and Solaris supporting the extra data transfer features of AGP video cards. ...

Versions of AGP

Intel released the first version of AGP; appropriately titled “AGP specification 1.0,” in 1997.^[5] It included both the 1x and 2x speeds.^[2] Specification 2.0 documented AGP 4X and 3.0 documented 8X.^[6][7] Available versions include:

AGP 1x

A 32-bit channel operating at 66 MHz resulting in a maximum data rate of 266 megabytes per second (MB/s), doubled from the 133 MB/s transfer rate of PCI bus 33 MHz / 32-bit; 3.3 V signaling.

AGP 2x

A 32-bit channel operating at 66 MHz double pumped to an effective 133 MHz resulting in a maximum data rate of 533 MB/s; signaling voltages the same as AGP 1x;

AGP 4x

A 32-bit channel operating at 66 MHz quad pumped to an effective 266 MHz resulting in a maximum data rate of 1066 MB/s (1 GB/s); 1.5 V signaling;

AGP 8x

A 32-bit channel operating at 66 MHz, strobing eight times per clock, delivering an effective 533 MHz resulting in a maximum data rate of 2133 MB/s (2 GB/s); 0.8 V signaling.

There are various physical interfaces (i.e. shape of slots), as explained in the Compatibility section below. 32-bit is a term applied to processors, and computer architectures which manipulate the address and data in 32-bit chunks. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... ReBoot character, see Megabyte (ReBoot). ... This article is about the computer bus type. ... In computing, a double pumped computer bus transfers data on both the rising and falling edges of the clock signal, effectively doubling the data transmission rate without having to deal with the additional problems of timing skew that increasing the number of data lines would introduce. ... Quadruple data rate (or quad pumping) is a microprocessor communication technique wherein data is transmitted four times for each clock cycle. ...

AGP version 3.5 is only publicly mentioned by Microsoft under Universal Accelerated Graphics Port (UAGP), which specifies mandatory supports of extra registers once marked optional under AGP 3.0. Upgraded registers include PCISTS, CAPPTR, NCAPID, AGPSTAT, AGPCMD, NISTAT, NICMD. New required registers include APBASELO, APBASEHI, AGPCTRL, APSIZE, NEPG, GARTLO, GARTHI.

Variations

A number of non-standard variations of the AGP interface have been produced by manufacturers.

64 bit AGP

A 64-bit channel. Used in high end professional graphic cards. It was once proposed as an optional standard for AGP 3.0 in draft documents, but was dropped in the final version of the standard.

AGP Express

Not a true AGP interface, but rather a way to allow an AGP card to be connected over the legacy PCI bus on a PCI Express motherboard. It is a technology found on ECS motherboards, and is used as a selling point for AGP card owners who want a new motherboard but do not want to be forced to buy a PCIe graphics card as well (most new motherboards do not provide AGP slots, only PCIe slots). An "AGP Express" slot is basically a PCI slot (with the electrical power of two) in the AGP form factor. While it offers backward compatibility with AGP cards, its disadvantages include incomplete support (some AGP cards do not work with AGP Express) and reduced performance - the card is forced to use the shared PCI bus at its lower bandwidth, rather than having exclusive use of the faster AGP.

AGI

The ASRock Graphics Interface (AGI) is a proprietary variant of the Accelerated Graphics Port (AGP) standard. Its purpose is to provide AGP-support for those of Asrock's motherboards that use chipsets lacking native AGP-support. However, it's not fully compatible and several videocard chipsets are known to not be supported.

AGX

The EpoX Advanced Graphics eXtended (AGX) is also a proprietary variant of the Accelerated Graphics Port (AGP) standard. It shares the same problems with the AGI port explained above. User manuals even recommend not using AGP 8X ATI cards with AGX slots.

Ultra-AGP, Ultra-AGPII

It is an internal AGP interface standard used by SiS for the north bridge controllers with integrated graphics. The original version supports same bandwidth as AGP 8x, while Ultra-AGPII has maximum 3.2GB/s bandwidth.

XGP

The Biostar Xtreme Graphics Port is also a variant of the Accelerated Graphics Port (AGP) standard. It is similar to the two standards above, in that it supports AGP cards with chipsets that do not support AGP. Also like the above, it has support issues with many AGP cards.

AGR

The Advanced Graphics Riser is a variation of the AGP port used in some PCIe motherboards to offer a limited backwards compatibility with AGP. It is, effectively, a modified PCI slot with no direct interconnection with the CPU or memory, and thus slower even compared to an AGP 1x slot. Its actual compatibility with AGP cards is also limited, while motherboard manufacturers usually publish a specific compatibility list.

AGP Pro

This was a rarely-used slot for cards that required more electrical power. It is a longer slot with additional pins for that purpose. AGP Pro cards were usually workstation-class cards used to accelerate professional computer-aided design applications employed in the fields of architecture, machining, engineering, simulations, and similar fields.

In computing, a 64-bit component is one in which data are processed or stored in 64-bit units (words). ... This article is about the computer bus type. ... PCI Express (formerly known as 3GIO for 3rd Generation I/O, not to be mistaken with PCI-X) is an implementation of the PCI computer bus that uses existing PCI programming concepts and communications standards, but bases it on a much faster serial communications system. ... Elitegroup Computer Systems (or ECS) is a Taiwan-based electronics firm. ... ASRock main board - KT400A chipset ASRock Incorporation, started in 2002 in Taiwan as an ASUS subsidiary. ... EPoX are a manufacturer of motherboards, video cards and communication products. ... Silicon Integrated Systems (SiS) is a company that manufactures, among other things, motherboards. ... This article does not adequately cite its references. ... CADD and CAD redirect here. ...

Compatibility

Compatibility, AGP Keys on card (top), on slot (bottom)

AGP cards are backward and forward compatible within limits. 1.5 V-only keyed cards will not go into 3.3 V slots and vice versa, though "Universal" slots exist which accept either type of card. AGP Pro cards will not fit into standard slots, but standard AGP cards will work in a Pro slot. Some newer cards, like NVIDIA's GeForce 6 series or ATI's Radeon X800 series, only have keys for 1.5 V to prevent them from installing in older mainboards without 1.5 V support. Some of the last modern cards with 3.3 V support were the NVIDIA GeForce FX series and the ATI Radeon 9500/9700/9800(R350) (but not 9600/9800(R360)). Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... In technology, especially computing (irrespective of platform), a product is said to be backward compatible (or upward compatible) when it is able to take the place of an older product, by interoperating with other products that were designed for the older product. ... Forward compatibility (sometimes confused with extensibility) is the ability of a system to accept input intended for later versions of itself. ... The GeForce 6 Series is nVidias newest series of graphics processors. ... The ATi Radeon X Series is the latest offering from graphics card manufacturer ATi Technologies. ... NVIDIA GeForce FX logo The famous Dawn demo was released by NVIDIA to showcase pixel and vertex shaders effects of the GeForce FX Series The GeForce FX (codenamed NV30) is a graphics card in the GeForce line, from the manufacturer NVIDIA. // Overview NVIDIAs GeForce FX series is the fifth... The Radeon R300 (introduced August 2002) is the third generation of Radeon graphics chips from ATI Technologies. ...

It is important to check voltage compatibility as some cards incorrectly have dual notches and some motherboards incorrectly have fully open slots. Furthermore, some poorly designed older 3.3 V cards incorrectly have the 1.5 V key. Inserting a card into a slot that does not support the correct signaling voltage may cause damage.

There are some proprietary exceptions to this rule. For example, Apple Power Macintosh computers with the Apple Display Connector have an extra connector which delivers power to the attached display. Additionally, moving cards between computers of various CPU architectures may not work due to firmware issues. Apple Inc. ... The Power Mac G5, the last model of the series. ... The Apple Display Connector (ADC) is a proprietary connector Apple used for their flat panel LCDs and their last CRT display. ... CPU design is the hardware design of a central processing unit. ... A microcontroller, like this PIC18F8720 is controlled by firmware stored inside on FLASH memory In computing, firmware is a computer program that is embedded in a hardware device, for example a microcontroller. ...

Use today

As of late 2007, few new motherboards feature AGP slots. No new motherboard chipsets are equipped with AGP support, but motherboards continue to be produced with older chipsets that have AGP support. PCI Express allows for higher data transfer rates, has more robust full-duplex support, and also supports other devices. PCI Express (formerly known as 3GIO for 3rd Generation I/O, not to be mistaken with PCI-X) is an implementation of the PCI computer bus that uses existing PCI programming concepts and communications standards, but bases it on a much faster serial communications system. ... A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. ...

All new graphics processors are designed for PCI-Express. To create AGP graphics cards, those chips require an additional PCIe to AGP bridge chip to convert PCIe signals to and from AGP signals. This incurs additional board costs due the need for the additional bridge chip and for a separate AGP-designed circuit board.

Various manufacturers of graphics cards continue to produce AGP cards for the shrinking AGP user-base. The first bridged cards were the GeForce 6600 and ATI Radeon X800 XL boards, released during 2004-5.^[8][9] As of late 2007, AGP cards from NVIDIA are limited to the older GeForce 7 series boards. The only DirectX 10-capable AGP cards are from ATI's Radeon HD 2400 and 2600 budget and mid-range lines.^[10] The GeForce 7 Series is the seventh generation of NVIDIAs GeForce graphics cards. ... Microsoft DirectX is a collection of application programming interfaces for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. ... The graphics processing unit (GPU) codenamed R600 is the foundation of the Radeon HD 2000 series and the FireGL 2007 series video cards developed by ATI Technologies. ...

See also

• List of device bandwidths
• PCI
• PCI Express

This is a list of device bandwidths: the channel capacity (or, more informally, bandwidth) of some computer devices employing methods of data transport is listed by bit/s, kilobit/s (kbit/s), megabit/s (Mbit/s), or gigabit/s (Gbit/s) as appropriate and also MB/s or megabytes per... This article is about the computer bus type. ... PCI Express (formerly known as 3GIO for 3rd Generation I/O, not to be mistaken with PCI-X) is an implementation of the PCI computer bus that uses existing PCI programming concepts and communications standards, but bases it on a much faster serial communications system. ...

References

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. This article does not cite any references or sources. ... “GFDL” redirects here. ...

External links

• AGP pinout
• AGP expansion slots
• AGP compatibility (with pictures)
• Ultra-AGPII Technology
• PCI Specifications Documents contains AGP specs.
• Universal Accelerated Graphics Port (UAGP)
• How Stuff Works - AGP