Bus is in the functions of computer parts (such as CPU, memory, hard disk, and all kinds of input and output devices) transfer of information between the commonly used communication lines. It is made up of wire transmission wire harness.

Bus standard module edge, pin positions and other technical specifications. Therefore, manufacturers can produce chips based on bus standards and specifications, and equipment (including hard disks).

SATA Bus is hard external Bus standard. Using serial connection mode, the interface is simple in structure, high transmission speed and execution efficiency, error correction ability strong, supporting hot plug, etc.

The PCI local bus - E bus standard is a kind of internal standard, is to replace PCI (Peripheral Component Interconnect) bus is put forward. It is a high-speed serial point-to-point two-channel high bandwidth transmission.

In PCI - E bus standard, connecting device is assigned a proprietary channel bandwidth, and do not share resources with other equipment. Main support active power management, bug reports, reliable end-to-end transmission, hot-swappable, quality of service (QOS), and other functions. Most importantly, it has a very high rate.

From the point of view of writing and reading speed, PCI - E bus priority in SATA bus standard. In SATA bus standard, the data of operation process is as follows: first, the data read from the hard disk into memory, and then to extract the CPU to calculate, write memory after calculation, the last in the hard disk.

In PCI - E bus standard, data directly connected to the CPU through the bus, don't need to call the ramdisk, make close to the maximum transmission speed transmission speed PCI - E.

But, speaking, reading and writing speed not only with the bus standard, but also affected by AHCI, NVMe data transfer protocol.