What is the difference between PCI and PCIe cards?

What is the difference between PCI and PCIe cards?

The difference between PCIE (PCI Express) and PCI is that it realizes the transformation of the transmission mode from parallel to serial. PCI Express uses a point-to-point serial connection, which is very different from the previous parallel channels. It allows the establishment of independent data transmission channels with each device. There is no need to request bandwidth from the entire system, so it is easy to achieve high bandwidth that is beyond the reach of other interface devices.

The PCI Express interface varies according to the different bit width requirements of the bus interface, and is divided into PCI Express1X, 2X, 4X, 8X, 16X and even 32X. Therefore, the length of the PCI Express interface is also different. 1X is the smallest and gets larger as you go up. At the same time, different PCI Express interfaces are also backward compatible with other products with small PCI Express interfaces.

That is, PCI Express4X devices can be plugged into PCI Express8X or 16X to work.

In addition, the PCI Express16X graphics interface will include its two channels, one from the graphics card to the Northbridge alone, and the other from the Northbridge to the graphics card alone. Each separate channel will have a data bandwidth of 4GB/s, which can fully avoid bandwidth problems. The performance bottleneck problem caused.

PCI Express can mainly bring us the following new features:

Performance: The PCI Express bus only requires a few pins from the chipset, so the difficulty of motherboard wiring is greatly reduced (the number of pins is about 75% less than the current PCI bus), but it has much higher performance than the current PCI Bandwidth and transmission speed, PCI Express is also superior to PCI in terms of configuration flexibility. It can use different frequencies to communicate with the hardware devices it is connected to.

Multiple connection methods: This is very different from the PCI bus. The PCI Express bus can "go out of the chassis". That is to say, PCI Express can connect and communicate with external devices that use corresponding PCI Express standard interfaces through certain interfaces on the computer, just like current USB or Firewire.

Point-to-point bus: Compared with the "bus-type" connection method of PCI, once a bottleneck occurs on the PCI bus, it will affect all PCI devices connected to it. The PCI Express bus uses point-to-point technology, so that each PCI Express device communicates directly with the system chip, without bandwidth issues.

Advanced features: PCI Express can use a variety of different signaling protocols including its own protocol. It also has advanced power management and monitoring capabilities so that all PCI Express devices are hot-swappable. Features such as memory error correction will become standard features in PCI Express.

Cross-platform compatibility: One of the biggest advantages of PCI Express is its cross-platform compatibility. Today's PCI 2, 3 compliant boards will be able to be used on low-bandwidth PCI Express slots. Using point-to-point connection technology, PCI Express has its own dedicated connection in each device and does not need to request bandwidth from the shared bus. To put it more bluntly, the goal of PCI Express is to realize I/O connections between chips, connections to expansion boards (such as graphics cards, sound cards), and even provide connection support for USB interfaces and IEEE 1394 interfaces.


The difference between PCI and PCI-E on the motherboard:

1. Different colors

PCI interfaces are usually white, and PCI-E interfaces generally use other colors to distinguish them from PCI interfaces.

2.  different lengths

The PCI-E interface is obviously longer than the PCI interface.