Accelerated Graphics Port (AGP) –

Overview:
AGP is a specialized interface standard introduced by Intel in 1997 to improve the speed and performance of 3D graphics on personal computers. Before AGP, graphics cards primarily used the PCI (Peripheral Component Interconnect) bus, which had limited bandwidth and shared the system bus with other devices, causing performance bottlenecks in graphics-intensive applications.

Purpose:
AGP was designed to provide a dedicated, high-bandwidth connection between the graphics card (GPU) and the system’s main memory, enabling more efficient handling of 3D graphics data, especially textures and geometry.

Key Features of AGP:

• Dedicated Pathway: AGP connects the GPU directly to the system memory, bypassing the traditional shared PCI bus.
• Pipelining: AGP allows multiple data requests to be sent at once without waiting for each to complete, improving efficiency.
• Sideband Addressing: It uses separate channels for addresses and data, enabling the GPU to send more information without delays.
• Direct Memory Execute (DIME): Enables the GPU to access texture data stored in system memory directly, reducing the need to copy everything to the graphics card’s local memory.
• Speeds: AGP came in several versions, including:
  • AGP 1x: 266 MB/s
  • AGP 2x: 533 MB/s
  • AGP 4x: 1.07 GB/s
  • AGP 8x: 2.1 GB/s (the final and fastest standard)

Comparison with PCI and PCIe:

Obsolescence:

AGP was widely used from the late 1990s through the early 2000s. However, it has been superseded by PCI Express (PCIe), which offers:

• Higher bandwidth
• Full-duplex data transmission
• Greater scalability

Today, all modern graphics cards use PCIe.

Use Cases –

AGP was particularly important for:

• Early 3D gaming
• CAD and 3D modelling
• Multimedia applications requiring real-time rendering