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TP General - What is AGP - Accelerated Graphics Port - Brief Overview
Applicable to: World-Wide
AGP provides enhanced video performance by moving video off the PCI bus and making use of standard system memory. To take full advantage of AGP, consider the available system memory, operating system, and application being run.
The Accelerated Graphics Port (AGP) interface is a platform bus specification that enables high performance graphics capabilities (especially 3D). Running 3D applications requires more memory than 2D applications. AGP moves graphics off the PCI bus, giving that bus more bandwidth for other I/O functions such as disk and network access.
An operating system needs drivers to recognize the AGP, and applications should be coded to take advantage of AGP performance. Under Windows 95, AGP support requires DirectX 5.0, OSR2.1, and an Intel driver (VGARTD.VXD). Certain AGP operating modes will still work fine without the updates to Windows 95. Windows 98 has and Windows 2000 will have native support for AGP. AGP-enabled graphics controllers can still perform without operating system support, but the full benefit can not be achieved
The AGP graphics controller has its own memory, but it can also use the main system memory. The AGP specification allows for dynamic allocation (and reallocation) of main memory. AGP is cost effective since the 3D functions can use the cheaper DRAM of main memory compared to having a large quantity of dedicated, expensive VRAM or WRAM on the graphics controller. So, AGP could provide the same level of performance from a graphics controller with 4MB of memory as a graphics controller with 8MB.
AGP neither replaces nor diminishes the necessity of PCI in the system. This high speed port (AGP) is physically, logically, and electrically independent of the PCI bus. It is not a bus because it is not shared by anything but the graphics controller. It is intended for the exclusive use of visual display devices; all other I/O devices will remain on the PCI bus.
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Date Created |
22-12-98 | |
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Last Updated |
22-12-98 | |
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Revision Date |
23-12-99 | |
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IBM ThinkPad | |
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ThinkPads General | |
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Various | |
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