PCI, pci-x, pci-e difference

PCI, pci-x, pci-e difference
One, PCI bus
The PCI bus standard was developed by Pcisig in 1992 and has a history of more than 8 years. Total bandwidth =33mhzx32bit/8=133mb/s for PCI.
Second, Pci-x bus
Pci-x is based on a PCI V2.2 version that adds power management capabilities and hot-swappable technology, increasing the total PCI bandwidth from 133mb/s to 1.066gb/s. At the same time, it also adopts the design of separation practice, multitasking, allows a device that is requesting data from a target device to handle anything else before the target device is ready; In the current PCI system, the device does not care about anything before it completes a request, and the bus clock cycle is wasted. At the same time Pci-x also allows the device is not ready to send data from the bus to remove, so that the bus bandwidth can be used by other transactions, so that the use of the bus greatly increased. Therefore, at the same frequency, Pci-x will be able to provide higher 14%~35% performance than PCI. Pci-x also uses the same 128Bit standard size block design as the IA-64, making the data blocks of the bus the same size, providing more pipelining and improved processor management.

Pci-x is currently divided into 66MHz, 100MHz and 133MHz three versions. The Pci-x controller working at 66MHz will be able to access up to 4 pci-x devices and, of course, can support more devices if pci-x to Pci-x bridge chips are added. 66MHz Pci-x has 533mb/s bandwidth. The Pci-x bus is shared, with 66,100 and 1333 species.

100MHz Pci-x devices are operating in 100MHz, at this time the Pci-x bus can only manage up to two pci-x devices, in the 64bit bus and 100MHz frequency, with 800mb/s bandwidth.

The most luxurious 133MHz pci-x work at 133MHz and will provide stunning 1066mb/s bandwidth.

Third, Pci-e bus
PCI Express is a new generation of graphics architecture that can provide a lot of bandwidth and rich functions. PCI Express can significantly increase the bandwidth between the central processing unit (CPU) and the graphics processor (GPU). For end users, they can experience theater-level images and have a seamless multimedia experiences.

Pci-x is not independent, according to the development of PCI bus: Pci-pcix-pcie, they are to improve the speed of PCI transmission. PCI is 32-bit 33MHz, PCIX is 64-bit to provide the highest 133MHz frequency, PCIe can be on the existing frequency through serial mode multi-channel combination to provide a higher speed, all future interfaces will be PCIe way, not just graphics cards.

PCI--E Bus is a completely different from the past PCI bus, a new bus specification, compared with PCI bus shared parallel architecture, PCI Express bus is a point-to-point serial connection device connection, point-to-point means that each PCI Express devices have their own independent data connection, the various devices of the concurrent data transmission between each other, and for the past PCI that shared bus mode, PCI bus can only have one device to communicate, once the PCI bus hook on the increase in the number of devices, the actual transmission rate of each device will be reduced, Performance is not guaranteed. Now, PCI Express processing communications in a point-to-point manner, each device when required to transmit data to establish their own transmission channel, for other devices this channel is closed, such operations to ensure the exclusive channel, to avoid interference from other devices.

Pci-x is the extended architecture of the PCI bus, Pci-x frequency is not as fixed as PCI, but can change as the device changes. Pci-x uses a 64-bit PCI bus that can support 66,100,133mhz these frequencies. And in the future, more frequency support may be available. The Pci-x standard is presented primarily for server I/O architectures. The goal of Pci-x is to increase the speed of transfer between the CPU and the peripherals, which can increase the server's I/O speed by twice times. Unlike the original PCI standard developers, the sequel to PCI was developed jointly by IBM and other machine-computer vendors.

Pci-x such ports are not visible on general PC motherboards, most of which are on the server board. This slot seems to be a reinforced type of PCI, with a long slot. It supports both Pci-x and PCI two card jacks.

Pci-express (PCI-E) is the latest bus and interface standard, its original name "3GIO", was proposed by Intel. Intel means that it represents the next generation I/O interface standards. Referred to Pci-sig (PCI Special Interest Organization) certification issued after the name "Pci-express". This new standard will completely replace the existing PCI and AGP, and ultimately achieve the unification of the bus standards. Its main advantage is that the data transmission rate is high, at present the maximum can reach 10gb/s above.
PCI Express Bandwidth (bidirectional transmission mode):
1 lane-x1:500mb/s
4 lane-x4:2gb/s (2000MB/S)
8 lane-x8:4gb/s (4000MB/S)
LANE-X16:8GB/S (8000MB/S)
Among them, X16 most common to, it is now basically replaced the AGP slot as the interface standard of the graphics card. Can provide 5gb/s bandwidth, while age 8X bandwidth is 2.1gb/s.

The X2 mode will be used for internal interfaces rather than slot mode. The PCI-E specification is connected to 32 channel connections from 1 channels, and has a very strong scalability to meet the different requirements of different system devices for data transmission bandwidth. In addition, a shorter pci-e card can be plugged into a longer pci-e slot, and the Pci-e interface can also support hot-plug.

Pci-x is proposed by Ibm,hp,compaq, which is a parallel interface and is a PCI correction, which is compatible with PCI.
Pci-e, also known as Pci-express, PCIe, is a serial interface that is not compatible with PCI, as proposed by Intel.
The trend now is that PCI-E will replace PCI and Pci-x as well as AGP, just as PCI replaces Isa.

The same method can be used to compute the bandwidth of a bus that is very much related to memory bandwidth, such as PCI and AGP. For example, PCI bandwidth =33mhzx32bit/8= 133MB/S,AGP 1X bus bandwidth of 66MHZX64BIT/8=528MB/S,AGP 4X bandwidth =528mhzx4=2.1gb/seconds.

Turn from: http://netnewsme.blogspot.com/2009/03/pcipci-xpci-e.html