Accelerated Graphics Port
Encyclopedia
The Accelerated Graphics Port (often shortened to AGP) is a high-speed point-to-point channel for attaching a video card
to a computer
's motherboard
, primarily to assist in the acceleration of 3D computer graphics
. Since 2004 AGP has been progressively phased out in favor of PCI Express
(PCIe). By mid-2009 PCIe cards dominated the market; AGP cards and motherboards were still produced, but OEM
driver support was minimal.
, a bus
with shared bandwidth. This led to the development of AGP, a "bus" dedicated to graphics adapters.
The primary advantage of AGP over PCI is that it provides a dedicated pathway between the slot and the processor rather than sharing the PCI bus. In addition to a lack of contention for the bus, the direct connection allows for higher clock speeds. AGP also uses sideband addressing, meaning that the address
and data buses are separated so the entire packet does not need to be read to get addressing information. This is done by adding eight extra 8-bit buses
which allow the graphics controller to issue new AGP requests and commands at the same time with other AGP data flowing via the main 32 address/data (AD) lines. This results in improved overall AGP data throughput.
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
, which reapportions main memory as needed for texture
storage, allowing the graphics card to access them directly. The maximum amount of system memory available to AGP is defined as the AGP aperture
.
Intel P5
Pentium and Slot 1
P6
Pentium II
processors. Intel introduced AGP support with the i440LX Slot 1 chipset on the August 26, 1997, and a flood of products followed from all the major system board vendors.
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.
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.)
Microsoft first introduced AGP support into Windows 95
OEM Service Release 2 (OSR2 version 1111 or 950B) via the USB SUPPLEMENT to OSR2 patch. 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.
There are various physical interfaces (connectors); see Compatibility section.
applications employed in the fields of architecture, machining, engineering, simulations, and similar fields.
channel was once proposed as an optional standard for AGP 3.0 in draft documents, but it was dropped in the final version of the standard.
The standard allows 64-bit transfer for AGP8× Reads, Writes, and Fast Writes; 32-bit transfer for PCI operations.
for the north bridge controllers with integrated graphics. The original version supports same bandwidth as AGP 8×, while Ultra-AGPII has maximum 3.2GB/s bandwidth.
and forward compatible
within limits. 1.5 V-only keyed cards will not go into 3.3 V slots and vice versa, though "Universal" cards exist which will fit into either type of slot. There are also unkeyed "Universal" slots that will accept either type of card. When an AGP Universal card is plugged-into an AGP Universal slot, only the 1.5 V portion of the card is used. Some cards, like Nvidia's GeForce 6 series (except the 6200) or ATI's Radeon X800 series, only have keys for 1.5 V to prevent them from being installed 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 (FX 5200, FX 5500, FX 5700, some FX 5800, FX 5900 and some FX 5950) and the ATI Radeon 9500/9700/9800(R350)
(but not 9600/9800(R360)). Some Geforce 6200 cards will function with AGP 1.0 (3.3v) slots.
AGP Pro cards will not fit into standard slots, but standard AGP cards will work in a Pro slot. Motherboards equipped with a Universal AGP Pro slot will accept a 1.5 V or 3.3 V card in either the AGP Pro or standard AGP configuration, a Universal AGP card, or a Universal AGP Pro card.
Some cards incorrectly have dual notches, and some motherboards incorrectly have fully open slots, allowing a card to be plugged into a slot that does not support the correct signaling voltage, which may damage card or motherboard. Some incorrectly-designed older 3.3 V cards have the 1.5 V key.
There are some proprietary systems incompatible with standard AGP; for example, Apple
Power Macintosh
computers with the Apple Display Connector
(ADC) have an extra connector which delivers power to the attached display. Some cards designed to work with a specific CPU architecture
(e.g., PC, Apple) may not work with others due to firmware
issues.
drawn from the various rails is given in the specifications for the various versions. For example, if maximum current is drawn from all supplies and all voltages are at their specified upper limits, an AGP 3.0 slot can supply up to 48.25 watt
s; this figure can be used to specify a power supply conservatively, but in practice a card is unlikely ever to draw more than 40 W from the slot, with many using less. AGP Pro provides additional power up to 110 W. Many AGP cards had additional power connectors to supply them with more power than the slot could provide.
Graphics processors of this period use PCI-Express, a general-purpose (not restricted to graphics) standard that supports higher data transfer rates and full-duplex
. To create AGP-compatible 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 to the need for the additional bridge chip and for a separate AGP-designed circuit board.
Various manufacturers of graphics cards continued 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. In 2009 AGP cards from Nvidia had a ceiling of the GeForce 7 Series
. In 2011 DirectX
10-capable AGP cards from AMD vendors (Club 3D, HIS, Sapphire, Jaton, Visiontek, Diamond, etc.) included the Radeon HD 2400, 3450, 3650
, 4350, 4650, and 4670
. The HD 5000 AGP series mentioned in the catalyst software was never available. There were many problems with the AMD Catalyst 11.2 - 11.6 AGP hotfix drivers under Windows 7 with the HD 4000 series AGP video cards; use of 10.12 or 11.1 AGP hotfix drivers is the recommended workaround. Several of the vendors listed above make available past versions of the AGP drivers.
Video card
A video card, Graphics Card, or Graphics adapter is an expansion card which generates output images to a display. Most video cards offer various functions such as accelerated rendering of 3D scenes and 2D graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors...
to a computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
's motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
, primarily to assist in the acceleration of 3D computer graphics
3D computer graphics
3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images...
. Since 2004 AGP has been progressively phased out in favor of PCI Express
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
(PCIe). By mid-2009 PCIe cards dominated the market; AGP cards and motherboards were still produced, but OEM
Original Equipment Manufacturer
An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...
driver support was minimal.
Advantages over PCI
As computers became increasingly graphically-oriented, successive generations of graphics adapters began to push the limits of PCIPeripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...
, a bus
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...
with shared bandwidth. This led to the development of AGP, a "bus" dedicated to graphics adapters.
The primary advantage of AGP over PCI is that it provides a dedicated pathway between the slot and the processor rather than sharing the PCI bus. In addition to a lack of contention for the bus, the direct connection allows for higher clock speeds. AGP also uses sideband addressing, meaning that the address
Address bus
An address bus is a computer bus that is used to specify a physical address. When a processor or DMA-enabled device needs to read or write to a memory location, it specifies that memory location on the address bus...
and data buses are separated so the entire packet does not need to be read to get addressing information. This is done by adding eight extra 8-bit buses
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...
which allow the graphics controller to issue new AGP requests and commands at the same time with other AGP data flowing via the main 32 address/data (AD) lines. This results in improved overall AGP data throughput.
In addition, to load a texture, a PCI graphics card must copy it from the system's RAM into the card's framebuffer
Framebuffer
A framebuffer is a video output device that drives a video display from a memory buffer containing a complete frame of data.The information in the memory buffer typically consists of color values for every pixel on the screen...
, whereas an AGP card is capable of reading textures directly from system RAM using the graphics address remapping table
Graphics address remapping table
The graphics address remapping table , sometimes known as the graphics translation table , is an I/O memory management unit used by AGP and PCI Express graphics cards. The GART allows the graphics card direct memory access to the host system memory, through which buffers of textures, polygon...
, which reapportions main memory as needed for texture
Texture mapping
Texture mapping is a method for adding detail, surface texture , or color to a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Dr Edwin Catmull in his Ph.D. thesis of 1974.-Texture mapping:...
storage, allowing the graphics card to access them directly. The maximum amount of system memory available to AGP is defined as the AGP aperture
Aperture (computer memory)
In computing, an aperture is a portion of the address space which is persistently associated with a particular peripheral device or a memory unit...
.
History
The AGP slot first appeared on x86 compatible system boards based on Socket 7Socket 7
Socket 7 is a physical and electrical specification for an x86-style CPU socket on a personal computer motherboard. The socket supersedes the earlier Socket 5, and accepts P5 Pentium microprocessors manufactured by Intel, as well as compatibles made by Cyrix/IBM, AMD, IDT and others.Socket 7 was...
Intel P5
P5 (microarchitecture)
The original Pentium microprocessor was introduced on March 22, 1993. Its microarchitecture, deemed P5, was Intel's fifth-generation and first superscalar x86 microarchitecture. As a direct extension of the 80486 architecture, it included dual integer pipelines, a faster FPU, wider data bus,...
Pentium and Slot 1
Slot 1
Slot 1 refers to the physical and electrical specification for the connector used by some of Intel's microprocessors, including the Pentium Pro, Celeron, Pentium II and the Pentium III...
P6
P6 (microarchitecture)
The P6 microarchitecture is the sixth generation Intel x86 microarchitecture, implemented by the Pentium Pro microprocessor that was introduced in November 1995. It is sometimes referred to as i686. It was succeeded by the NetBurst microarchitecture in 2000, but eventually revived in the Pentium M...
Pentium II
Pentium II
The Pentium II brand refers to Intel's sixth-generation microarchitecture and x86-compatible microprocessors introduced on May 7, 1997. Containing 7.5 million transistors, the Pentium II featured an improved version of the first P6-generation core of the Pentium Pro, which contained 5.5 million...
processors. Intel introduced AGP support with the i440LX Slot 1 chipset on the August 26, 1997, and a flood of products followed from all the major system board vendors.
The first Socket 7 chipsets to support AGP were the VIA
VIA Technologies
VIA Technologies is a Taiwanese manufacturer of integrated circuits, mainly motherboard chipsets, CPUs, and memory, and is part of the Formosa Plastics Group. It is the world's largest independent manufacturer of motherboard chipsets...
Apollo VP3
Apollo VP3
Apollo VP3 is a x86 based Socket 7 chipset which was manufactured by VIA Technologies and was launched 1997. y.On its time Apollo VP3 was a high performance, cost effective, and energy efficient chipset. It offered AGP support for Socket 7 processors which was not supported at that moment by...
, SiS
Silicon Integrated Systems
Silicon Integrated Systems is a company that manufactures, among other things, motherboard chipsets. The company was founded in 1987 in Hsinchu Science Park, Taiwan.-Business:...
5591/5592, and the ALI
Acer Laboratories Incorporated
Acer Laboratories Incorporated is a major designer and manufacturer of integrated circuits for the personal computer and embedded systems markets. It is a subsidiary of the Acer group....
Aladdin V. Intel never released an AGP-equipped Socket 7 chipset. FIC
First International Computer
First International Computer, Inc. is a Taiwanese computer and components manufacturer, that designs and manufactures computer products and electronic components for other electronics equipment manufacturers worldwide. The company's products include motherboards, embedded computing systems,...
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.
Early video chipsets featuring AGP support included the Rendition
Rendition (company)
Rendition was a maker of 3D graphics chipsets in the mid- to late-90's. They were known for products such as the Vérité 1000 and Vérité 2x00 and for being one of the first 3D chipset makers to directly work with Quake developer John Carmack to make a hardware-accelerated version of the game ....
Vérité V2200, 3dfx
3dfx
3dfx Interactive was a company that specialized in the manufacturing of 3D graphics processing units and, later, graphics cards. It was a pioneer in the field for several years in the late 1990s until 2000 when it underwent one of the most high-profile demises in the history of the PC industry...
Voodoo Banshee, Nvidia
NVIDIA
Nvidia is an American global technology company based in Santa Clara, California. Nvidia is best known for its graphics processors . Nvidia and chief rival AMD Graphics Techonologies have dominated the high performance GPU market, pushing other manufacturers to smaller, niche roles...
RIVA 128
RIVA 128
Released in late 1997 by Nvidia, the RIVA 128, or "NV3", was one of the first consumer graphics processing units to integrate 3D acceleration in addition to traditional 2D and video acceleration...
, 3Dlabs
3Dlabs
3DLABS was the name of the fabless semiconductor company that originally developed the GLINT and PERMEDIA high-end graphics chip technology that was used on many of the worlds leading computer graphics cards in the CAD and DCC markets, including its own Wildcat and Oxygen cards.In 2006 the company...
PERMEDIA 2, Intel i740
Intel740
The Intel740, or i740, is a graphics processing unit using an AGP interface released by Intel in 1998. Intel was hoping to use the i740 to popularize the AGP port, while most graphics vendors were still using PCI. Released with enormous fanfare, the i740 proved to have disappointing real-world...
, ATI Rage series
ATI Rage
The ATI Rage is a series of graphics chipsets offering GUI 2D acceleration, video acceleration, and 3D acceleration. It is the successor to the Mach series of 2D accelerators.-3D RAGE :...
, Matrox
Matrox
Matrox is a producer of video card components and equipment for personal computers. Based in Dorval, Quebec, Canada it was founded by Lorne Trottier and Branko Matić....
Millennium II, and S3 ViRGE GX/2
S3 ViRGE
The S3 Virtual Reality Graphics Engine graphics chipset was one of the first 2D/3D accelerators designed for the mass market.-Introduction:...
. 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.)
Microsoft first introduced AGP support into Windows 95
Windows 95
Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
OEM Service Release 2 (OSR2 version 1111 or 950B) via the USB SUPPLEMENT to OSR2 patch. 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
Windows NT 4.0
Windows NT 4.0 is a preemptive, graphical and business-oriented operating system designed to work with either uniprocessor or symmetric multi-processor computers. It was the next release of Microsoft's Windows NT line of operating systems and was released to manufacturing on 31 July 1996...
with service pack
Service pack
A service pack is a collection of updates, fixes or enhancements to a software program delivered in the form of a single installable package. Many companies, such as Microsoft or Autodesk, typically release a service pack when the number of individual patches to a given program reaches a certain ...
3, introduced in 1997. Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
support for AGP enhanced fast data transfers was first added in 1999 with the implementation of the AGPgart kernel module.
Versions
Intel released "AGP specification 1.0" in 1997. It included both the 1× and 2× speeds. Specification 2.0 documented AGP 4× and 3.0 documented 8×. Available versions include:| Specification | Speed | Pumping | Rate (MB/s) | Frequency (MHz) | Voltage (V) |
|---|---|---|---|---|---|
| PCI | - | single | 133 | 33 | 3.3 |
| AGP 1.0 | 1× | single | 266 | 66 | 3.3 |
| AGP 1.0 | 2× | double | 533 | 66 | 3.3 |
| AGP 2.0 | 4× | quad | 1066 | 66 | 1.5 |
| AGP 3.0 | 8× | octuple | 2133 | 66 | 0.8 |
| AGP 3.5 * | 8× | octuple | 2133 | 66 | 0.8 |
- 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.
There are various physical interfaces (connectors); see Compatibility section.
Official extensions
AGP Pro
It is an official extension 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 designComputer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...
applications employed in the fields of architecture, machining, engineering, simulations, and similar fields.
64-bit AGP
A 64-bit64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...
channel was once proposed as an optional standard for AGP 3.0 in draft documents, but it was dropped in the final version of the standard.
The standard allows 64-bit transfer for AGP8× Reads, Writes, and Fast Writes; 32-bit transfer for PCI operations.
Unofficial variations
A number of non-standard variations of the AGP interface have been produced by manufacturers.Internal AGP interface
Ultra-AGP, Ultra-AGPII: It is an internal AGP interface standard used by SiSSilicon Integrated Systems
Silicon Integrated Systems is a company that manufactures, among other things, motherboard chipsets. The company was founded in 1987 in Hsinchu Science Park, Taiwan.-Business:...
for the north bridge controllers with integrated graphics. The original version supports same bandwidth as AGP 8×, while Ultra-AGPII has maximum 3.2GB/s bandwidth.
PCI-based AGP ports
-
- AGP Express: Not a true AGP interface, but allows an AGP card to be connected over the legacy PCI busPeripheral Component InterconnectConventional PCI is a computer bus for attaching hardware devices in a computer...
on a PCI ExpressPCI ExpressPCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
motherboard. It is a technology used on motherboards made by ECSElitegroup Computer SystemsElitegroup Computer Systems Co., Ltd , is a Taiwan-based electronics firm. It is the fifth largest PC motherboard manufacturer in the world , with production reaching 24 million units in 2002...
, intended to allow an existing AGP card to be used in a new motherboard instead of requiring a PCIe card to be obtained (since the introduction of PCIe graphics cards few motherboards provide AGP slots). An "AGP Express" slot is basically a PCI slot (with twice the electrical power) with an AGP connector. It offers backward compatibility with AGP cards, but provides 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 ASRock motherboards that use chipsets lacking native AGP support. However, it is not fully compatible wih AGP, and several video card chipsets are known not to be supported.
- AGX: The EpoXEPoXEPoX was a manufacturer of motherboards, video cards and communication products. They manufactured mainboards for AMD and Intel processors, which are renowned for being overclocker-friendly yet affordable. Many of their products used the same StudlyCaps naming convention as the company...
Advanced Graphics eXtended (AGX) is another proprietary AGP variant with the same advantages and disadvantages as AGI. User manuals recommend not using AGP 8× ATI cards with AGX slots. - XGP: The BiostarBiostarBiostar or Biostar Microtech International Corp, is a motherboard manufacturer based in Taiwan, designing and manufacturing of computer hardware products such as motherboards, video cards, barebone computers and industrial PCs, to meet the demands of market development by providing more integrated...
Xtreme Graphics Port is another AGP variant, also with the same advantages and disadvantages as AGI and AGX.
- AGP Express: Not a true AGP interface, but allows an AGP card to be connected over the legacy PCI bus
PCIe based AGP ports
-
- AGR: The Advanced Graphics RiserAdvanced Graphics RiserThe Advanced Graphics Riser is a variation of the AGP port used in some PCIe motherboards made by MSI to offer a limited backwards compatibility with AGP. It is, effectively, a modified PCIe slot allowing for performance comparable to an AGP 4x/8x slot , but with limited support of AGP cards...
is a variation of the AGP port used in some PCIe motherboards made by MSIMicro-Star InternationalMicro-Star International Co., Ltd is a Taiwan-based electronics company and one of the world's largest motherboard and video card manufacturers.-Overview:MSI is one of the top three motherboard and video card manufacturers worldwide...
to offer limited backwards compatibility with AGP. It is, effectively, a modified PCIe slot allowing for performance comparable to an AGP 4×/8× slot, but does not support all AGP cards; the manufacturer published a list of some cards and chipsets that work with the modified slot.
- AGR: The Advanced Graphics Riser
Compatibility
AGP cards are backwardBackward compatibility
In the context of telecommunications and computing, a device or technology is said to be backward or downward compatible if it can work with input generated by an older device...
and forward compatible
Forward compatibility
Forward compatibility or upward compatibility is a compatibility concept for systems design, as e.g. backward compatibility. Forward compatibility aims at the ability of a design to gracefully accept input intended for later versions of itself...
within limits. 1.5 V-only keyed cards will not go into 3.3 V slots and vice versa, though "Universal" cards exist which will fit into either type of slot. There are also unkeyed "Universal" slots that will accept either type of card. When an AGP Universal card is plugged-into an AGP Universal slot, only the 1.5 V portion of the card is used. Some cards, like Nvidia's GeForce 6 series (except the 6200) or ATI's Radeon X800 series, only have keys for 1.5 V to prevent them from being installed in older mainboards without 1.5 V support. Some of the last modern cards with 3.3 V support were the Nvidia GeForce FX
GeForce FX
The GeForce FX or "GeForce 5" series is a line of graphics processing units from the manufacturer NVIDIA.-Overview:...
series (FX 5200, FX 5500, FX 5700, some FX 5800, FX 5900 and some FX 5950) and the ATI Radeon 9500/9700/9800(R350)
Radeon R300
The Radeon R300 is the third generation of Radeon graphics chips from ATI Technologies. The line features 3D acceleration based upon Direct3D 9.0 and OpenGL 2.0, a major improvement in features and performance compared to the preceding Radeon R200 design. R300 was the first fully Direct3D...
(but not 9600/9800(R360)). Some Geforce 6200 cards will function with AGP 1.0 (3.3v) slots.
AGP Pro cards will not fit into standard slots, but standard AGP cards will work in a Pro slot. Motherboards equipped with a Universal AGP Pro slot will accept a 1.5 V or 3.3 V card in either the AGP Pro or standard AGP configuration, a Universal AGP card, or a Universal AGP Pro card.
Some cards incorrectly have dual notches, and some motherboards incorrectly have fully open slots, allowing a card to be plugged into a slot that does not support the correct signaling voltage, which may damage card or motherboard. Some incorrectly-designed older 3.3 V cards have the 1.5 V key.
There are some proprietary systems incompatible with standard AGP; for example, Apple
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
Power Macintosh
Power Macintosh
Power Macintosh, later Power Mac, was a line of Apple Macintosh workstation-class personal computers based on various models of PowerPC microprocessors that were developed, marketed, and supported by Apple Inc. from March 1994 until August 2006. The first models were the Power Macintosh 6100,...
computers with the Apple Display Connector
Apple Display Connector
The Apple Display Connector is a proprietary modification of the DVI connector that combines analog and digital video signals, USB, and power all in one cable...
(ADC) have an extra connector which delivers power to the attached display. Some cards designed to work with a specific CPU architecture
CPU design
CPU design is the design engineering task of creating a central processing unit , a component of computer hardware. It is a subfield of electronics engineering and computer engineering.- Overview :CPU design focuses on these areas:...
(e.g., PC, Apple) may not work with others due to firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
issues.
Power consumption
Actual power supplied by an AGP slot depends upon the card used. The maximum currentElectric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
drawn from the various rails is given in the specifications for the various versions. For example, if maximum current is drawn from all supplies and all voltages are at their specified upper limits, an AGP 3.0 slot can supply up to 48.25 watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
s; this figure can be used to specify a power supply conservatively, but in practice a card is unlikely ever to draw more than 40 W from the slot, with many using less. AGP Pro provides additional power up to 110 W. Many AGP cards had additional power connectors to supply them with more power than the slot could provide.
Legacy use
By 2010 few new motherboards had AGP slots. No new motherboard chipsets were equipped with AGP support, but motherboards continued to be produced with older chipsets with support for AGP.Graphics processors of this period use PCI-Express, a general-purpose (not restricted to graphics) standard that supports higher data transfer rates and full-duplex
Duplex (telecommunications)
A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....
. To create AGP-compatible 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 to the need for the additional bridge chip and for a separate AGP-designed circuit board.
Various manufacturers of graphics cards continued 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. In 2009 AGP cards from Nvidia had a ceiling of the GeForce 7 Series
GeForce 7 Series
The GeForce 7 Series is the seventh generation of Nvidia's GeForce graphics processing units.-Features:The following features are common to all models in the GeForce 7 series except the GeForce 7100, which lacks GCAA:-GeForce 7100 Series:...
. In 2011 DirectX
DirectX
Microsoft DirectX is a collection of application programming interfaces for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with Direct, such as Direct3D, DirectDraw, DirectMusic, DirectPlay,...
10-capable AGP cards from AMD vendors (Club 3D, HIS, Sapphire, Jaton, Visiontek, Diamond, etc.) included the Radeon HD 2400, 3450, 3650
Radeon R600
The graphics processing unit codenamed the Radeon R600 is the foundation of the Radeon HD 2000/3000 series and the FireGL 2007 series video cards developed by ATI Technologies...
, 4350, 4650, and 4670
Radeon R700
The Radeon R700 is the engineering codename for a graphics processing unit series developed by Advanced Micro Devices under the ATI brand name. The foundation chip, codenamed RV770, was announced and demonstrated on June 16, 2008 as part of the FireStream 9250 and Cinema 2.0 initiative launch media...
. The HD 5000 AGP series mentioned in the catalyst software was never available. There were many problems with the AMD Catalyst 11.2 - 11.6 AGP hotfix drivers under Windows 7 with the HD 4000 series AGP video cards; use of 10.12 or 11.1 AGP hotfix drivers is the recommended workaround. Several of the vendors listed above make available past versions of the AGP drivers.
See also
- List of device bandwidths
- Serial Digital Video Out for ADD DVI adapter cards
External links
- Archived AGP Implementors Forum
- AGP specifications: 1.0, 2.0, 3.0, Pro 1.0, Pro 1.1a
- AGP Compatibility For Sticklers
- 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
- A discussion from 2003 of what AGP aperture is, how it works, and how much memory should be allocated to it.