How AGP Works

With the greater technological innovations, computing has become more advanced and faster by the day. These days email, files, streaming of movies or video games, is ruled by graphics! In such a scenario what is it that makes the computer work so fast, with all the graphics and extra effects involved? There is only one answer this question – AGP or Accelerated Graphics Port. However, in order for you to understand the function of AGP, it is important to understand how your computer would run without an AGP!

Computing in time of PCI bus

All the graphics and connected content that runs on your computer comes from the working of a graphic card. Before AGP arrived in the markets, the computers used PCI or Peripheral Component Interconnect buses for running graphics and other devices connected to the computer. Now PCI bus is a path that makes way for any device to send information to the CPU of the computer. With this bus, it is possible for several devices to send multiple packets of information to the computer, all at one time. The graphics card information too would travel through this bus. However, during times of congestion, the graphics information had to wait in long lines, hence slowing down the function of the graphics card, thereby slowing its performance as well.

Enter AGP

Then AGP or Accelerated Graphics Port came into being! This port was built especially for the graphics card, making a path for it to transmit information to the CPU directly, providing a point-to-pint connection. Thus, the AGP was able to lend the computer information in a much faster manner, making it easy for graphics to function efficiently.

How AGP works.

The main aim of AGP was to improve data transportation to the CPU, while working on similar lines to PCI. However, the company involved in the development of AGP – Intel – ensured that they took care of all the bottlenecks that were slowing down the data transfer in PCI. This resulted in the ability of AGP to deliver data at much faster rates, hence improving the ability of the computer to process graphics and related information. Some of the reasons that impart AGP its speed are:

Dedicated port – AGP could be connected to no device other than a graphic card. Therefore, the graphics card can operate to its maximum capability.

Faster Response time – This method of response was termed as pipelining, which lets the graphics card receive and respond to several data packets with one request only.

Sideband Addressing – For every packet of information sent, there is a need for an address – sending “to” and sent “from”. With PCI, comprehending these addresses was extremely complicated. However, with sideband addressing used by AGP, where it uses additional eight lines for addressing on data packet, it becomes easier and hence, faster! AGP, unlike PCI, labels the address on the outside of the envelope. This saves on a lot of bandwidth that would be used in taking the data out and keeping it back inside in the envelope. This helps unclog the system, while making the transmission of data faster.

Graphic Card specific RAM allocation – The speed of AGP is further enhanced as it asks the OS to designate certain specific RAM for the graphic card only. This memory is often called AGP memory or non-local video memory. Hence, with more texture maps being stored on RAM, the graphics card memory does not feel over-burned and hence performs faster. Then again, this also allows AGP to store a texture map only once (instead of twice like in PCI). This further reduces the burden on the operating system, speeding up the entire process.

AGP is now becoming standard with several computers and other electronic devices like mobile phones, notebooks etc.

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