PCI Express

PCI_Express

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PCI_Express_Terminology

PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-E, is a high-speed serial communication computer expansion bus standard designed to replace the older PCI, PCI-X, and AGP bus standards. It is used to connect various hardware devices to a computer's motherboard.

Overview

PCI Express is a point-to-point architecture that provides a high-speed data transfer interface between the computer's central processing unit (CPU) and attached devices. Unlike its predecessors, which used a shared parallel bus architecture, PCIe uses a serial interface that allows for higher data transfer rates and improved performance.

Architecture

PCIe architecture consists of multiple lanes, each consisting of two pairs of wires, one for sending and one for receiving data. The number of lanes can vary, with common configurations being x1, x4, x8, and x16. The more lanes a PCIe slot has, the higher the potential data transfer rate.

Link

A PCIe link is composed of one or more lanes. Each lane is a full-duplex byte stream, transporting data packets in both directions simultaneously. The link width is determined by the number of lanes, and it can be scaled to meet the performance requirements of different devices.

Slots and Form Factors

PCIe slots come in various sizes, corresponding to the number of lanes they support. The most common form factors are:

• x1
• x4
• x8
• x16

These slots are backward compatible, meaning a smaller card can fit into a larger slot and function correctly, albeit at the lower bandwidth of the smaller card.

Versions

PCIe has undergone several revisions since its inception, each offering improvements in data transfer rates and features:

• PCIe 1.0: 2.5 GT/s (Giga-transfers per second)
• PCIe 2.0: 5 GT/s
• PCIe 3.0: 8 GT/s
• PCIe 4.0: 16 GT/s
• PCIe 5.0: 32 GT/s
• PCIe 6.0: 64 GT/s

Applications

PCIe is widely used in various applications, including:

• Graphics cards
• Solid-state drives (SSDs)
• Network interface controllers (NICs)
• Sound cards
• RAID controllers

Advantages

Some of the key advantages of PCIe include:

• Higher data transfer rates compared to older standards
• Scalable architecture
• Lower latency
• Improved error detection and correction mechanisms

Related Pages

• PCI
• PCI-X
• AGP
• Motherboard
• Central processing unit
• Graphics card
• Solid-state drive
• Network interface controller
• Sound card
• RAID

See Also

• Serial communication
• Computer expansion bus
• Data transfer rate