What is AGP and AGP Pro?

As fast and wide as the PCI bus was, there was one task that threatened to consume all its bandwidth: displaying graphics. Early in the era of the ISA bus, monitors were driven by simple Monochrome Display adapter (MDA) and Colour Graphics Array (CGA) cards. A CGA graphics display could show four colours (two bits of data) at 320 by 200 pixels screen resolution at 60Hz, which required 128,000 bits of data per screen, or just over 937 KBps. An XGA image at a 16-bit colour depth requires 1.5MB of data for every image, and at a vertical refresh rate of 75Hz, this amount of data is required 75 times each second. Thanks to modern graphics adapters, not all of this data has to be transferred across the expansion bus, but 3D imaging technology created new problems. 3D graphics have made it possible to model both fantastic and realistic worlds on-screen in enormous detail. Texture mapping and object hiding require huge amounts of data, and the graphics adapter needs to have fast access to this data to avoid the AGP operates at the speed of the processor bus, now known as the frontside bus. At a clock rate of 66MHz this is double the PCI clock speed and means that the peak base throughput is 264 MBps. For graphics cards specifically designed to support it, AGP allows data to be sent during both the up and down clock cycle, doubling the clock rate to 133MHz and peak transfer to 528 MBps. This is known as 2x. To improve the length of time that AGP can maintain this peak transfer,...

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