Editing PCI Express (section)

{{short description|Computer expansion bus standard}}
{{Distinguish|PCI-X|UCIe}}
{{For|Engineering, Procurement, Construction and Installation|EPCI}}
{{use dmy dates |date=October 2020}}
{{Infobox computer hardware bus
| name = PCI Express
| fullname = Peripheral Component Interconnect Express
| image = PCI Express.svg{{!}}class=skin-invert
| invent-date = {{Start date and age|2003}}
| invent-name = {{Hlist
  | [[Intel]]
  | [[Dell]]
  | [[Hewlett-Packard|HP]]
  | [[IBM]]
  }}
| super-name =
| super-date =
| replaces = {{Hlist
  | [[Peripheral Component Interconnect|PCI]]
  | [[PCI-X]]
  | [[Accelerated Graphics Port|AGP]]
  }}
| width = 1 per lane<ref name="auto">{{cite book | url=https://books.google.com/books?id=ZjyrAgAAQBAJ&dq=pcie+dual+simplex&pg=PA69 | isbn=978-0-7384-5121-3 | title=IBM Power 770 and 780 Technical Overview and Introduction | date=6 June 2013 | publisher=IBM Redbooks }}</ref> {{Small|(up to 16 lanes)}}
| numdev = 1 on each endpoint of each connection.{{Efn|Switches can create multiple endpoints out of one to allow sharing it with multiple devices.}}
| speed = [[Dual simplex]], up to 242&nbsp;GB/s
| style = s
| hotplug = Optional {{Small|(support with [[ExpressCard]], [[#PCI Express OCuLink|OCuLink]], [[CFexpress]] or [[U.2]])}}
| external = Optional {{Small|(support with [[#PCI Express OCuLink|OCuLink]] or [[#PCI Express External Cabling|PCI Express External Cabling]])}}
| website = {{URL|https://pcisig.com/}}
}}
[[File:LSI_9207-4i4e_PCI-E_SAS_HBA.jpg|thumb|A PCIe 3.0 x8 [[host bus adapter]]]]

[[File:PCI-E & PCI slots on DFI LanParty nF4 SLI-DR 20050531.jpg|thumb|Various slots on a [[computer motherboard]], from top to bottom: {{unordered list
 | PCI Express x4
 | PCI Express x16
 | PCI Express x1
 | PCI Express x16
 | [[Conventional PCI]] (32-bit, 5&nbsp;V)
}}]]

'''PCI Express''' ('''Peripheral Component Interconnect Express'''), officially abbreviated as '''PCIe''' or '''PCI-E''',<ref name="s5NDG" /> is a high-speed [[serial communication|serial]] [[computer]] [[expansion bus]] standard, meant to replace the older [[Conventional PCI|PCI]], [[PCI-X]] and [[Accelerated Graphics Port|AGP]] bus standards. It is the common [[motherboard]] interface for personal computers' [[Video card|graphics cards]], [[Capture card|capture cards]], [[sound card]]s, [[hard disk drive]] [[host adapter]]s, [[Solid-state drive|SSDs]], [[Wi-Fi]], and [[Ethernet]] hardware connections.<ref name="DQmzv" /> PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count, smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER),<ref name="gf9Lm" /> and native [[Hot swapping|hot-swap]] functionality. More recent revisions of the PCIe standard provide hardware support for [[I/O virtualization]].

The PCI Express electrical interface is measured by the number of simultaneous lanes.<ref name="sxOen"/> (A lane is a set of send and receive data lines, analogous to a road having one lane of traffic in each direction.) The interface is also used in a variety of other standards — most notably the [[laptop]] expansion card interface called [[ExpressCard]]. It is also used in the storage interfaces of [[SATA Express]], [[U.2]] (SFF-8639) and [[M.2]].

Formal specifications are maintained and developed by the [[PCI-SIG]] (PCI [[Special Interest Group]]) — a group of more than 900 companies that also maintains the [[conventional PCI]] specifications.