Peripheral Component Interconnect Express , commonly known asPCIe , stands as a pivotal technology in the realm of data processor ironware . It provide a high - speed interface for connecting peripheral devices ( such as keyboard , speech sound cards , or outside hard drives , to name a few ) to a data processor ’s motherboard . From its origin to its current iteration , PCIe has continually evolved to converge the demands of New computing .
Whether you ’re a figurer partisan acute on building your own scheme or but curious about the mechanics behind your equipment ’s operation , you ’re in luck . In this article , we ’ll study what crap PCIe different from PCI . We ’ll also take care at how PCI Express makes a computing gadget faster , can potentially add nontextual matter execution , and can replace the Accelerated Graphics Port ( AGP ) time slot .
The Need for a PCIe Interface
Peripheral Component Interconnect ( PCI ) slots are such an integral part of a computer ’s architecture that most the great unwashed take them for granted . For yr , PCI has been a versatile , functional means to connectsound , television and connection plug-in to amotherboard .
But PCI has some shortcoming . Asprocessors , video card , well-grounded cards and web have get faster and more brawny , PCI has stayed the same . It has a get width of 32bitsand can deal only 5 devices at a clip . The new , 64 - bit PCI - X charabanc provides more bandwidth , but its not bad width compounds some of PCI ’s other issues .
Fortunately , PCI Express ( PCIe ) eliminates a mess of these shortcomings , allow for more bandwidth , and is compatible with existing operating systems .
High-Speed Serial Connection
In the other days of computation , a vast amount of datum propel overserialconnections . Computers separated data into mailboat and then moved thepacketsfrom one topographic point to another one at a time . sequent connector were dependable but dull , so manufacturers began usingparallelconnections to send multiple slice of data simultaneously .
It plow out that parallel connections have their own problem as speeds get higher and higher — for example , wires can interpose with each other electromagnetically — so now the pendulum is swing over back toward extremely - optimized consecutive connection . improvement to hardware and to the process of dividing , labeling and reassembling packets have lead to much faster consecutive connections , such asUSB 2.0andFireWire .
The Advantage of PCIe Devices
PCI Express is a serial connection that engage more like a electronic connection than abus . rather of one bus that handles data point from multiple sources , PCIe has a switch that controls several point - to - head serial connexion . ( SeeHow LAN Switches Workfor details . )
These connexion fan out from the switch , leading directly to the devices where the data point needs to go . Every gadget has its own consecrate connection , so devices no longer portion out bandwidth like they do on a normal bus . We ’ll wait at how this happens in the next section .
The Data Transfer Rate of PCIe Lanes
When the calculator starts up , PCI expressage slots determine which devices are plugged into the motherboard . It then identify the links between the devices , creating a map of where traffic will go and negociate the width of each link . This recognition of devices and link is the same protocol PCI uses , so PCIe does not expect any changes to software or operating systems .
Each PCIe lane contains two pairs of wires — one to send and one to get . Packets of data point move across the lane at a rate of one bit per cycle . A x1 link , the small PCIe link , has one lane made up of four telegram . It carries one bit per cycle in each direction . A x2 link incorporate eight wire and channel two bit at once , a x4 link transmits four bits , and so on . Other configurations are x12 , x16 and x32 .
Peripheral Component Interconnect Express is usable for background and laptopPCs . Its enjoyment may contribute to lower cost of motherboard output , since its connections control few pins than PCI connections do . It also has the electric potential to support many devices , includingEthernetcards , USB 2and video recording cards .
But how can one sequent connection be faster than the 32 wires of PCI or the 64 wires of PCIx ? In the next subdivision , we ’ll look at how PCIe is able to provide a immense amount of bandwidth in a serial data format .
PCI Express Connection Speeds
The 32 - bit PCI motorcoach has a maximal speed of 33 Mc , which take into account a upper limit of 133 MB of data to exit through the bus per second . The 64 - act PCI - X bus has twice the coach breadth of PCI . dissimilar PCI - X specification countenance unlike rates of information transfer of training , anywhere from 512 MB to 1 GB of datum per minute .
A single PCIe lane , however , can plow 200 MB of dealings in each direction per second . A x16 PCIe connection can move an awe-inspiring 6.4 GB of information per second in each direction . At these speeds , a x1 connective can well deal a gigabit Ethernet connexion as well as audio andstorage applications . A x16 connection can easily handle sinewy artwork adapter .
How is this possible ? A few simple advances have contributed to this massive leap in sequent joining speed :
PCIe Card and Advanced Graphics
We ’ve established that the data data link layer of PCIe can eliminate the need for an AGP connection . A x16 PCIe slot can accommodate far more data per 2nd than current AGP 8x connection leave .
In addition , a x16 PCIe slot can supply 75 James Watt of power to the video posting , as opposed to the 25watt/42 watt AGP 8x connective . But PCIe has even more impressive potential difference in store for the future of graphics technology .
Manufacturers Leveraging External PCI Express
With the veracious hardware , a motherboard with two x16 PCIe connection can stand two graphics adapters at the same time . Several manufacturer are develop and releasing systems to take advantage of this feature :
NVIDIA Scalable Link Interface(SLI ): With an SLI - certified motherboard , two SLI graphics cards and an SLI connector , a user can put two telecasting poster into the same system . The carte work together by separate the screen in one-half . Each poster controls half of the screen , and the connector makes certain that everything stays synchronized .
ATI CrossFire : Two ATI Radeon telecasting circuit board , one with a " compositing engine " chipping , plug into a compatible motherboard . ATI ’s technology focuses on trope timber and does not command identical picture cards , although high - performance arrangement must have identical add-in . Crossfire divides up the work of rendering in one of three way :
Alienware Video Array : Two off - the - shelf video card merge with a Video Merger Hub and proprietary software . This organisation will use specialized cooling and power system to treat all the supernumerary heat and energy from the video card . Alienware ’s technology may eventually support as many as four video recording bill of fare .
The PCI Express Standard
Since PCI , PCI - X , and PCI Express are all compatible , all three can coexist indefinitely . So far , video cards have made the quick modulation to the PCIe formatting .
meshwork and sound adapters , as well as other computer peripheral , have been slower in ontogeny . But since PCIe is compatible with current operating systems and can channelise data at faster speeds to multiple gimmick , it is potential that it will eventually put back PCI as a PC standard . Gradually , PCI - base cards will become disused .
For more information about PCI Express and related to subject , moderate out the links on the next pageboy .
This article was update in connective with AI technology , then fact - check and delete by a HowStuffWorks editor .
