A high-speed peripheral interconnect from Intel introduced in 2002. Note that although sometimes abbreviated "PCX," PCI Express is not the same as "PCI-X" (see PCI-SIG and PCI-X for comparison). As a result of the confusion, "PCI-E" or "PCIe" is the accepted abbreviation.
Initially used for high-speed display adapters, and intending to eventually replace the PCI and AGP buses entirely, PCI Express was designed to match the higher speeds of today's CPUs. It can accommodate Gigabit and 10 Gigabit Ethernet and even support chip-to-chip transfers.
Switched Architecture
Rather than the shared, parallel bus structure of PCI, PCI Express provides a switched architecture using serial communications channels, each made up of two differential wire pairs that provide 2.5 Gbits/sec in both directions. Up to 32 channels ("lanes") may be combined in x2, x4, x8, x16 and x32 configurations, creating a parallel interface of independently controlled channels. The bandwidth of the switch backplane determines the total capacity of a PCI Express implementation.
Internal in 2002, External in 2007
Similar in architecture to InfiniBand, PCI Express was initially designed for internal connections, whereas InfiniBand provides a true fabric architecture for external networks. However, enhancements that extended PCI Express outside of the box for several meters were developed in 2007. External PCI Express allows, for example, a laptop computer to hook up to an external display adapter and monitor, providing greater performance than the laptop's internal display adapter.
Different Slots
Originally called "Third Generation I/O" (3GIO), PCI Express is software compatible with PCI, but not plug compatible. It also uses slots of different lengths because of the combined lanes (see below). For a comparison of all PCI technologies, see PCI-SIG. See ExpressCard and PCI-X.
PCI Express Slot
PCI Express slots are both shorter and longer than PCI and AGP. The x1 slot is a single-lane implementation, while the x16 slot combines 16 lanes for peripherals such as the display adapter.
PCI-Express Vs. AGP
This display adapter from NVIDIA was one of the first x16 PCI Express cards on the market. PCI Express, AGP and PCI cards all have different edge connectors to ensure that they fit into the appropriate slots. (Image courtesy of NVIDIA Corporation.)
Initially used for high-speed display adapters, and intending to eventually replace the PCI and AGP buses entirely, PCI Express was designed to match the higher speeds of today's CPUs. It can accommodate Gigabit and 10 Gigabit Ethernet and even support chip-to-chip transfers.
Switched Architecture
Rather than the shared, parallel bus structure of PCI, PCI Express provides a switched architecture using serial communications channels, each made up of two differential wire pairs that provide 2.5 Gbits/sec in both directions. Up to 32 channels ("lanes") may be combined in x2, x4, x8, x16 and x32 configurations, creating a parallel interface of independently controlled channels. The bandwidth of the switch backplane determines the total capacity of a PCI Express implementation.
Internal in 2002, External in 2007
Similar in architecture to InfiniBand, PCI Express was initially designed for internal connections, whereas InfiniBand provides a true fabric architecture for external networks. However, enhancements that extended PCI Express outside of the box for several meters were developed in 2007. External PCI Express allows, for example, a laptop computer to hook up to an external display adapter and monitor, providing greater performance than the laptop's internal display adapter.
Different Slots
Originally called "Third Generation I/O" (3GIO), PCI Express is software compatible with PCI, but not plug compatible. It also uses slots of different lengths because of the combined lanes (see below). For a comparison of all PCI technologies, see PCI-SIG. See ExpressCard and PCI-X.
PCI Express Slot
PCI Express slots are both shorter and longer than PCI and AGP. The x1 slot is a single-lane implementation, while the x16 slot combines 16 lanes for peripherals such as the display adapter.
PCI-Express Vs. AGP
This display adapter from NVIDIA was one of the first x16 PCI Express cards on the market. PCI Express, AGP and PCI cards all have different edge connectors to ensure that they fit into the appropriate slots. (Image courtesy of NVIDIA Corporation.)
 | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2008 The Computer Language Company Inc. All rights reserved. |
Additional Resources
- Stolen: Google employees' personal data
- Names, addresses, and Social Security numbers of pre-2006 staffers were taken from offices of Colt Express Outsourcing Services. Google has confirmed that personal data of U.S. employees hired prior to 2006 have been stolen in a recent burglary. Records kept at Colt Express Outsourcing Services, an external...
- News items 2008-07-03
- I have to stop using Gmail :(
- I have to stop using Gmail :(You can enable POP3 support in Gmail...If you switch on POP3 support in Gmail, then you can still comply with archiving procedures: http://mail.google.com/support/bin/answer.py?hl=en&answer=13273That way, you can both send and receive e-mails with an e-mail client like Thunderbird or Evolution or even Outlook Express. I...
- Discussion threads 2008-07-03
- News to know: Searching Silverlight; IE 8; Dell; Google vs. YouTube
- Notable headlines: Mary Jo Foley: Microsoft: Silverlight content searchable, too Ryan Stewart: Brian Goldfarb talks about Silverlight 2 and Deep Zoom with Michael Cot LineRider releases a Silverlight 2 version Microsoft steps up self-policing of its OSI-approved source licenses ...
- Blog posts 2008-07-03
- Almeza MultiSet Automatic Software Installer (exe)
- A tool for creating a bootable disk with the Windows 2000/XP/2003/Vista operating systems. You can quickly install an operating system on a computer from such a disk. While creating it, MultiSet also allows you to integrate some service packs and, if necessary, remove some components from the operating system (Media...
- Software downloads 2008-07-03
- PCI-DSS 1.1 points to outdated OWASP Top 10
- OK, I'm not going to freak out about this too bad... I've already pointed out enough problems with PCI, but I did find it morbidly entertaining. My good friend Jeremiah Grossman pictured at right blogged today about the PCI-DSS 1.1 section 6.5, which covers "prevention of common coding vulnerabilities in...
- Blog posts 2008-07-02
- McAfee S.P.A.M. experiment and more ridiculous HackerSafe failures
- McAfee S.P.A.M. experiment and more ridiculous HackerSafe failuresI get slammed for pronouncing the name wrong, but McAfee is the bestMcAfee is the only true voice on security. I have never once seen a computer with their AV software installed that has be overrun with viruses. If this is...
- Discussion threads 2008-07-02
- Freeway Express (php)
- Whether you are an HTML pro, a designer with traditional training and work-experience or a novice to the exciting world of the Web Freeways integrated design environment makes life easy. Offering advanced functionality blended with a superbly accessible user interface, Freeway is designed to encompass the whole workflow; including the...
- Software downloads 2008-07-02
- McAfee S.P.A.M. experiment and more ridiculous HackerSafe failures
- Stay with me here readers, I'm stringing two stories about McAfee together here, a little out of the ordinary, so I hope it makes sense. If you aren't interested in the tech details of which there are very little, please do read for a good laugh. Network World reported...
- Blog posts 2008-07-01
- Sanmaxi Outlook Express Password Recovery (zip)
- Outlook Express Password Recovery Software restore all configure lost users accounts passwords. If any users have changed your MS Outlook Express account password without your knowledge, you can easily retrieve it. And change it further to avoid unauthorized access of your outlook express account. Easy to use software support to...
- Software downloads 2008-07-01
- Find nearby printers easily
- I was reading on10 a few days ago and came across a brilliant post. Xerox have created a driver which plugs straight into Windows, and searches for printers close to your physical location. For the life of me, I can't work out how it does it, but...
- Blog posts 2008-06-30
- Asus Eee PC 901 (Windows XP)
- We've been impressed by the Asus Eee PC line from the very first 7-inch model in the fall of 2007, and it seems as if every time we turn around, there's a new version hitting store shelves. This 9-inch version, the
- Product reviews 2008-06-30
- A world ruled by Apple
- A world ruled by AppleGood post[i]I am perfectly willing to praise Apple or Linux when I feel they are doing something right, and do so on a regular basis in this blog. That’s why I have a hard time understanding the need to believe that Gates did nothing right, in...
- Discussion threads 2008-06-30
- Open-Xchange releases preview of next groupware server for Web 2.0 era
- Open-Xchange has released a preview version of its next generation open source collaboration server designed for the Web 2.0 era. Open-Xchange Server Edition, which will succeed Open-Xchange 6 and Open-Xchange Express Edition, features an Ajax-based, customizable user interface for managing emails, contacts, task and document sharing, new...
- Blog posts 2008-06-30
- Bad leadership causes failed IT [guest blogger]
- Bad leadership causes failed IT [guest blogger]From the Obvious to the executionMuch of what you say is true, and as you point out much has been written on this subject, and very little changes.Having delivered some very successful projects myself, the biggest success factor is a clear delineation between, business,...
- Discussion threads 2008-06-29
- Bill Gates bids farewell
- Bill Gates bids farewellHe brought a lot to the computer world!Yeah, vicious predation, greed, and arrogance.iMiss BilliWill miss Bill. He brought a lot to the computer world!Bill Gates bids farewellA fine speech from a magnificent man! He had visions, he had missions, he had it all! The IT...
- Discussion threads 2008-06-27
- Top hotel sites in Q1 2008
- Q1 2007 Q1 2008 Percent Change Y/Y Intercontinental Hotel Brands 55.1 48.5 -12% Holiday Inn 30.7 30.8 1% Holiday Inn Express 16.2 18.8 16% Crowne Plaza 13.4 7.9 -41% Intercontinental 6.6 4.9 -26% Source: comScore by NB
- Blog posts 2008-06-27
- (Fun with openSUSE 11.0)
- (Fun with openSUSE 11.0)But it's not Blue Like Windows ...Let's see who runs with that.I'm running OpenSuSE 11 on 2 machines and love both the KDE and GNOME desktop implementations. And, as an added surprise, all the server bits are there as well.If you've looked at Ubuntu or other...
- Discussion threads 2008-06-27
- Dell Studio 15
- Parsing the intended markets for Dell's ever-shifting in-house brand names requires a bit of tea-leaf reading, although it's been easier of late, with the company stripping down its consumer brands to just the Inspiron and XPS lines. Now the company is adding a new line between the budget Inspiron and...
- Product reviews 2008-06-26
- Microsoft's geeks might miss Gates the most
- Microsoft's geeks might miss Gates the mostBrilliance = Techie + Financial ManagerialI think one of the reasons Microsoft has been so succesful is that Bill Gates was adept not necessarily the best at both spectrums: the techie and the business side. Witness General Motors under the "Smith" bean counter tenure:...
- Discussion threads 2008-06-26
- Valentine Love Screensaver 1 (exe)
- Valentine's Day is a holiday celebrated on February 14. In the America and Europe, it is the traditional day on which lovers express their love for each other by sending Valentine's cards, presenting flowers, or offering confectionery. Celebrate Valentine's day every day with this free screensaver. This version is the...
- Software downloads 2008-06-26
Neighboring Terms
Premier Vendor Content Whitepapers, webcasts & resources from our Power Center Sponsors
- ZDNet News Videos
-
Tech news covering the latest in products, conferences and blog commentary, from ZDNet video.
- Watch the latest video >>
-
-
Tasty Baking’s new LEED factory
0:57
Tasty Baking CIO: Brendan O’Malley
-
Balancing act: innovation vs. reliability
1:28
Facebook VP of technical operations: Jonathan Heiliger
-
Securing data at E-Loan
1:47
E-Loan CIO: Jay Shah
-
When crops are scarce
1:47
Del Monte Foods CIO: Marc Brown
- View all CIO Vision Series Videos »
