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PCI cards: FAQ:
What is PCI?
Intel developed PCI (Peripheral Component Interconnect) in the early 1990s as a general I/O
architecture. It is a multi-drop, parallel bus architecture that at the time of development could
theoretically transfer four times more data than the fastest I/O busses of that time. Over the
past decade PCI has become the de facto standard for I/O in the computing industry.
However, going forward it is becoming increasingly clear that the demands of tomorrows
processors and I/O devices are much higher than PCI can deliver.
Typical PCI card
What is PCI Express (PCIe)?
PCI Express (PCIe) is a new, much-anticipated, serial I/O architecture that is now entering the
marketplace after years of development, with companies like Emulex, Intel, Dell, HP, Microsoft
and IBM leading the way. Formerly known as Third Generation I/O (3GIO), this new
technology is expected by many to be the successor to the enduring PCI interface, improving
on performance while enabling significantly lower cost via a simplified architecture.
Typical PCIe card
What is the difference between PCI and PCI Express?
Essentially PCI Express replaces the multi-drop, parallel, PCI bus architecture, with a new
switching, serial bus architecture. Instead of a number of devices having to arbitrate for control
of a shared bus, PCIe uses a switch to create high-speed peer-to-peer links, eliminating many
of the inefficiencies associated with the bus architecture and significantly improving I/O
performance. PCI Express also uses fewer pins, which simplifies the design of I/O cards and
the system board.
Why was PCIe Created?
The systems interconnect demands of emerging computing and communications platforms
exceed the capabilities of traditional parallel buses like PCI. Technical innovations such as
faster CPU speeds, faster memories, high-performance graphics, multiple gigabit/second
(Gb/s) networking, storage, and communications interfaces, and high-speed consumer devices
are driving the need for a system interconnect with much greater bandwidth and flexibility than
PCI offers today.
Will PCIe replace PCI/PCI-X?
Eventually. For the foreseeable future, the two technologies will co-exist and both be
supported by the PCI-SIG and the IT industry, in general. Individual companies will choose the
best technology for their particular application. This is similar to the technology transition from
ISA to PCI.
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