The amount of data that can be transmitted over a line per unit of time, commonly measured in bits per second (bps)
The bandwidth of a computer network is the maximum rate of data that can pass through the network, i.e., how many bits per second.
Bit per second is often omitted when describing bandwidth.
For example, a bandwidth of 10 M is actually 10 Mb/s.
The M in this case is 10^6.
There are two different rates in a network:
The rate at which a signal (i.e., an electromagnetic wave) travels through a transmission medium (meters/second, or kilometers/second)
The rate at which a computer sends bits to a network (bits/second)
These two rates are the rate at which a computer sends bits to a network (bits/second). p>
These two rates have completely different meanings and units.
Before understanding the concept of bandwidth, let's first look at a formula: bandwidth = clock frequency x number of bus bits / 8, from the formula, we can see that the bandwidth and clock frequency, the number of bus bits is a very close relationship. In fact, in a computer system, not only the monitor, memory has the concept of bandwidth, in a board, the concept of bandwidth is more, can be said to be bandwidth everywhere.
What exactly is bandwidth? What is the meaning of bandwidth? Simply put, bandwidth is the transmission rate, is the maximum number of bytes per second (MB/S), that is, how many megabytes per second processing, high bandwidth means that the system's high processing power. In order to more graphically understand the relationship between bandwidth, bit width, clock frequency, we give a more graphic example, workers processing parts, if a person to do, in the case of everyone's individual processing speed is the same, certainly not as much as two people to do, the bandwidth is like the total number of parts processed, the bit width as if the number of workers, the clock frequency is equivalent to the processing of a single part of the speed, the wider the width of the bit width, the higher the clock frequency is The wider the bit width and the higher the clock frequency, the greater the bus bandwidth, and the benefits are obvious.
There are usually two large chips on the motherboard, generally known as the north bridge near the CPU and the south bridge away from the CPU. The role of the North Bridge is to establish a communication interface between the CPU and the memory and graphics card, and the amount of bandwidth they have to connect to the North Bridge largely determines the amount of memory and graphics card performance. The South Bridge is responsible for the computer's I/O devices, PCL devices and hard disk, the bandwidth requirements, compared to the North Bridge, is a little smaller. The bandwidth of the connection between the North and South Bridges is generally referred to as the North and South Bridge bandwidth. With the computer more and more to the direction of multimedia development, the South Bridge function is also increasingly powerful, for the North and South Bridge between the connection bus bandwidth is also put forward new requirements, in INTEL's 9X5 series of motherboards, North and South Bridge bandwidth will be from the previous has been criticized for the development of 266MB / S to the unprecedented 2GB / S, in one fell swoop, to solve the North and South Bridge between the bottleneck of the bandwidth.
Referring to graphics cards, friends who play games know that when playing some of the big games, the screen sometimes gets stuck. In fact, this is the problem of insufficient bandwidth on the graphics card, and to be more specific, insufficient memory bandwidth. As we all know, the current current AGP interface is AGP 8X, and the AGP bus frequency is twice the PCI bus, that is, 66MHz, it is easy to convert its bandwidth is 2.1GB / S, in the current environment, such a bandwidth appears to be very insignificant, because even the most common ATI R9000 memory bandwidth to reach 400MHZ X 128Bit/8=6.4GB/s, and the rest of the high-end graphics cards are even more so. Because of this, INTEL in the latest 9X5 chipset, the use of PCI-Express bus to replace the old AGP bus, with the traditional PCI and earlier computer bus **** enjoy parallel architecture compared to the biggest feature of PCI Express is the use of point-to-point serial connection between the devices, so that allows each device has its own dedicated Connection, do not need to request bandwidth to the entire bus, while using the characteristics of the serial connection will be able to easily data transfer speed to a very high frequency. In addition, because PCI Express supports bi-directional transfer modes, each connected device can utilize the maximum amount of bandwidth available, eliminating the bandwidth bottleneck experienced by AGP.
In order to get more bus bandwidth in the actual use of the computer, based on the bandwidth calculation formula, two approaches are generally taken, one is to increase the bus speed, for example, INTEL's P4 CPU and Celeron CPU is the best example, one is the 400 bus, and the other one is the 533/800 bus, in the actual application of the efficacy of the big difference (of course.). L2 cache is also an important factor). Another common method is to increase the width of the bus. If the width of the bus is doubled when the clock speed is the same, then the amount of data transferred per falling edge is twice as much as before, even though the clock falling edge is the same as before, which is especially noticeable on cards with the same core but different memory bit-widths.
[u]Web Hosting[/u]
Some web hosting providers give bandwidth a different meaning. Here again, bandwidth almost becomes a traffic concept. It means the total amount of downlinked data for a specified period of time. It means that if a web hosting company gives you 2GB of bandwidth per month, then it means that your users can only download up to 2GB of content per month.In website hosting, bandwidth is the amount of information downloadable from the In website hosting, bandwidth is the amount of information downloadable from the webserver over a prescribed period of time. In essence, it is the rate [data/time], but the time in this case is not seconds but rather a month or a week. this rate is not like 56K or broadband, etc., which are also bandwidth but are measured per second. Web hosting companies often quote a monthly bandwidth limit for a website, for example 2K or 1K. Web hosting companies often quote a monthly bandwidth limit for a website, for example 2GB/month. If visitors to the website download a total greater than 2GB in one month, the bandwidth limit will have been If visitors to the website download a total greater than 2GB in one month, the bandwidth limit will have been exceeded.