In personal computers A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator. This is in contrast to the batch processing or time-sharing models which allowed large expensive mainframe, the front-side bus (FSB) is the bus In computer architecture, a bus is a subsystem that transfers data between computer components inside a computer or between computers that carries data between the CPU The Central Processing Unit or the processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. This term has been in use in the computer industry at least since the early 1960s . The form, design and implementation of CPUs have changed and the northbridge The northbridge, also known as a memory controller hub or an integrated memory controller (IMC) in Intel systems (AMD, VIA, SiS and others usually use 'northbridge'), is one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Separating the chipset into the northbridge and southbridge is common,.
Depending on the processor used, some computers may also have a back-side bus that connects the CPU to the cache A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations. As long as most memory accesses are cached memory locations, the average latency of memory accesses will be. This bus and the cache connected to it are faster than accessing the system memory (or RAM) via the front-side bus.
The bandwidth In computer networking and computer science, bandwidth, digital bandwidth, or network bandwidth is a measure of available or consumed data communication resources expressed in bit/s or multiples of it or maximum theoretical throughput of the front-side bus is determined by the product of the width of its data path, its clock frequency The clock rate is the rate in cycles per second for the frequency of the clock in any synchronous circuit (such as a CPU). For example, a crystal oscillator frequency reference typically is synonymous with a fixed sinusoidal waveform, a clock rate is that frequency reference translated by electronic circuitry (AD Converter) into a corresponding (cycles per second) and the number of data transfers it performs per clock cycle. For example, a 64-bit A bit or binary digit is the basic unit of information in computing and telecommunications; it is the amount of information that can be stored by a digital device or other physical system that can usually exist in only two distinct states. These may be the two stable positions of an electrical switch, two distinct voltage or current levels allowed (8-byte The byte is a unit of digital information in computing and telecommunications. It is an ordered collection of bits, in which each bit denotes the binary value of 1 or 0. Historically, a byte was the number of bits (typically 5, 6, 7, 8, 9, or 16) used to encode a single character of text in a computer and it is for this reason the basic) wide FSB operating at a frequency of 100 MHz that performs 4 transfers per cycle has a bandwidth of 3200 megabytes The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: 1048576 bytes generally for computer memory; and one million bytes (106, see prefix mega-) generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000 000", with per second (MB/s).
The number of transfers per clock cycle is dependent on the technology used. For example, GTL+ performs 1 transfer/cycle, EV6 2 transfers/cycle, and AGTL+ 4 transfers/cycle. Intel calls the technique of four transfers per cycle Quad Pumping.
Many manufacturers publish the speed of the FSB in MHz, but often do not use the actual physical clock frequency but the theoretical effective data rate (which is commonly called megatransfers Transfer or the more common derivatives Gigatransfer and Megatransfer (MT) are terms used in computer technology, referring to a number of data transfers (or operations). They are most commonly used for measuring transfer rates (usually as transfers per second, GT/s, MT/s, etc.). 1 GT/s means 109 or one (US/short scale) billion transfers per per second or MT/s). This is because the actual speed is determined by how many transfers can be performed by each clock cycle as well as by the clock frequency. For example, if a motherboard (or processor) has a FSB clocked at 200 MHz and performs 4 transfers per clock cycle, the FSB is rated at 800 MT/s.
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History and current usage
The front-side bus is an alternative name for the data and address buses of the CPU as defined by the manufacturer's datasheet A datasheet, data sheet, or spec sheet is a document summarizing the performance and other technical characteristics of a product, machine, component , material, a subsystem (e.g. a power supply) or software in sufficient detail to be used by a design engineer to integrate the component into a system. Typically, a datasheet is created by the. The term is mostly associated with the various CPU buses used on PC-related motherboards A motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the main board, system board, or, on Apple computers, the logic board. It is also sometimes casually shortened to (including servers etc), seldom with the data and address buses used in embedded systems An embedded system is a computer system designed to perform one or a few dedicated functions often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal computer , is designed to be flexible and to meet a wide and similar small computers.
Front-side buses serve as a connection between the CPU The central processing unit or the processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. It is the unit that reads and executes program instructions. The data in the instruction tells the processor what to do. The instructions are and the rest of the hardware via a chipset A chipset, PC chipset or chip set refers to a group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product. This chipset is usually divided in a northbridge The northbridge, also known as a memory controller hub or an integrated memory controller (IMC) in Intel systems (AMD, VIA, SiS and others usually use 'northbridge'), is one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Separating the chipset into the northbridge and southbridge is common, and a southbridge The Southbridge, also known as an I/O Controller Hub or a Platform Controller Hub (PCH) in Intel systems (AMD, VIA, SiS and others usually use 'southbridge'), is a chip that implements the "slower" capabilities of the motherboard in a northbridge/southbridge chipset computer architecture. The southbridge can usually be distinguished from part,and is the connection point for all other buses in the system. Buses like the PCI Conventional PCI is a computer bus for attaching hardware devices in a computer. These devices can take either the form of an integrated circuit fitted onto the motherboard itself, called a planar device in the PCI specification, or an expansion card that fits into a slot. The name PCI is an initialism formed from Peripheral Component Interconnect, AGP The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004, AGP has been progressively phased out in favor of PCI Express. As of mid-2009, PCIe cards dominate the market, but new AGP cards and motherboards, and memory buses all connect to the chipset in order for data to flow between the connected devices. These secondary system buses usually run at speeds derived from the front-side bus clock, but are not necessarily synchronous In computer science, synchronization refers to one of two distinct but related concepts: synchronization of processes, and synchronization of data. Process synchronization refers to the idea that multiple processes are to join up or handshake at a certain point, so as to reach an agreement or commit to a certain sequence of action. Data to it.
In response to AMD Advanced Micro Devices, Inc. (NYSE: AMD) is an American multinational semiconductor company based in Sunnyvale, California, that develops computer processors and related technologies for commercial and consumer markets. Its main products include microprocessors, motherboard chipsets, embedded processors and graphics processors for servers,'s Torrenza initiative, Intel has opened its FSB CPU socket to third party devices [1] [2]. Prior to this announcement, made in Spring 2007 at Intel Developer Forum in Beijing Beijing , also known as Peking (pronounced /piːˈkɪŋ/ or /peɪˈkɪŋ/), is a metropolis in northern China, and the capital of the People's Republic of China. Governed as a municipality under direct administration of the central government, Beijing borders Hebei Province to the north, west, south, and for a small section in the east, and, Intel had very closely guarded who had access to the FSB, only allowing Intel processors in the CPU socket. This is now changing, the first example being FPGA A field-programmable gate array is a semiconductor device that can be configured by the customer or designer after manufacturing—hence the name "field-programmable". FPGAs are programmed using a logic circuit diagram or a source code in a hardware description language (HDL) to specify how the chip will work. They can be used to co-processors, a result of collaboration between Intel Intel Corporation is a technology company, and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most personal computers. Intel was founded on July 18, 1968, as Integrated Electronics Corporation (though a common misconception is that "Intel"-Xilinx Xilinx, Inc. is a supplier of programmable logic devices. It is known for inventing the field programmable gate array (FPGA) and as the first semiconductor company with a fabless manufacturing model-Nallatech Nallatech is a Scottish computer hardware and software firm based in Cumbernauld in North Lanarkshire, Scotland that specializes in field-programmable gate array microchip technology applied in computing. The company was founded by Allan Cantle in 1993 and is backed by over £4m of equity finance provided by Scottish Equity Partners and 3i [3] and Intel-Altera Altera Corporation is a Silicon Valley manufacturer of PLDs (programmable logic devices). The company invented the first reprogrammable logic device in 1984. PLDs can be reprogrammed during the design cycle as well as in the field to perform multiple functions, and they support a fairly fast design process. Altera's main products are the Cyclone,-XtremeData [4] [5].
Related component speeds
CPU
The frequency Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency. The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency. Loosely speaking, 1 year is the period of the Earth's orbit around the Sun, and the Earth's rotation on its axis has at which a processor (CPU) operates is determined by applying a clock multiplier to the front-side bus (FSB) speed in some cases. For example, a processor running at 3200 MHz The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of sine wave, particularly those used in radio and audio applications might be using a 400 MHz FSB. This means there is an internal clock multiplier setting (also called bus/core ratio) of 8. That is, the CPU is set to run at 8 times the frequency of the front-side bus: 400 MHz × 8 = 3200 MHz. By varying either the FSB or the multiplier, different CPU speeds can be achieved.
Memory
See also: Memory dividerSetting a FSB speed is related directly to the speed grade of memory a system must use. The memory bus connects the northbridge and RAM, just as the front-side bus connects the CPU and northbridge. Often, these two buses must operate at the same frequency. Increasing the front-side bus to 450 MHz in most cases also means running the memory at 450 MHz.
In newer systems, it is possible to see memory ratios of "4:5" and the like. The memory will run 5/4 times as fast as the FSB in this situation, meaning a 400 MHz bus can run with the memory at 500 MHz. This is often referred to as an 'asynchronous' system. It is important to realize that due to differences in CPU and system architecture, overall system performance can vary in unexpected ways with different FSB-to-memory ratios.
In image An image is an artifact, for example a two-dimensional picture, that has a similar appearance to some subject—usually a physical object or a person, audio Sound recording and reproduction is an electrical or mechanical inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording. Acoustic analog recording is achieved by a small microphone diaphragm that, video Motion graphics are graphics that use video and/or animation technology to create the illusion of motion or a transforming appearance. These motion graphics are usually combined with audio for use in multimedia projects. Motion graphics are usually displayed via electronic media technology, but may be displayed via manual powered technology as, gaming A video game is an electronic game that involves interaction with a user interface to generate visual feedback on a video device. The word video in video game traditionally referred to a raster display device. However, with the popular use of the term "video game," it now implies any type of display device. The electronic systems used to, FPGA A field-programmable gate array is a semiconductor device that can be configured by the customer or designer after manufacturing—hence the name "field-programmable". FPGAs are programmed using a logic circuit diagram or a source code in a hardware description language (HDL) to specify how the chip will work. They can be used to synthesis and scientific applications that perform a small amount of work on each element of a large data set A data set is a collection of data, usually presented in tabular form. Each column represents a particular variable. Each row corresponds to a given member of the data set in question. Its values for each of the variables, such as height and weight of an object or values of random numbers. Each value is known as a datum. The data set may comprise, FSB speed becomes a major performance issue. A slow FSB will cause the CPU to spend significant amounts of time waiting for data to arrive from system memory Random-access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order (i.e., at random). "Random" refers to the idea that any piece of data can be returned in a constant time, regardless of its physical location and whether or not it is related to the. However, if the computations involving each element are more complex, the processor will spend longer performing these; therefore, the FSB will be able to keep pace because the rate at which the memory is accessed is reduced.
Peripheral buses
Similar to the memory bus, the PCI and AGP buses can also be run asynchronously from the front-side bus. In older systems, these buses are operated at a set fraction of the front-side bus frequency. This fraction was set by the BIOS In IBM PC Compatible computers, the basic input/output system , also known as the System BIOS, is a de facto standard defining a firmware interface. In newer systems, the PCI, AGP, and PCI Express PCI Express , officially abbreviated as PCIe (or PCI-E, as it is commonly called), is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP standards. PCIe 2.1 is the latest standard for expansion cards that is available on mainstream personal computers peripheral buses often receive their own clock signals In electronics and especially synchronous digital circuits, a clock signal is a particular type of signal that oscillates between a high and a low state and is utilized like a metronome to coordinate actions of circuits. Although the word signal has a number of other meanings, the term is here used for "transmitted energy that can carry, which eliminates their dependence on the front-side bus for timing.
Overclocking
Main article: Overclocking Overclocking is the process of running a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, usually practiced by enthusiasts seeking an increase in the performance of their computers. Some purchase low-end computer components which they then overclock to higher clock rates, or overclock high-Overclocking Overclocking is the process of running a computer component at a higher clock rate than it was designed for or was specified by the manufacturer, usually practiced by enthusiasts seeking an increase in the performance of their computers. Some purchase low-end computer components which they then overclock to higher clock rates, or overclock high- is the practice of making computer components operate beyond their stock performance levels.
Many motherboards allow the user to manually set the clock multiplier and FSB settings by changing jumpers or BIOS settings. Almost all CPU manufacturers now "lock" a preset multiplier setting into the chip. It is possible to unlock some locked CPUs; for instance, some Athlons Athlon is the brand name applied to a series of x86-compatible microprocessors designed and manufactured by Advanced Micro Devices . The original Athlon (now called Athlon Classic) was the first seventh-generation x86 processor and, in a first, retained the initial performance lead it had over Intel's competing processors for a significant period can be unlocked by connecting electrical contacts An electrical connector is a conductive device for joining electrical circuits together. The connection may be temporary, as for portable equipment, or may require a tool for assembly and removal, or may be a permanent electrical joint between two wires or devices. There are hundreds of types of electrical connectors. In computing, an electrical across points on the CPU's surface. For all processors, increasing the FSB speed can be done to boost processing speed by reducing latency Latency in a packet-switched network is measured either one-way , or round-trip (the one-way latency from source to destination plus the one-way latency from the destination back to the source). Round-trip latency is more often quoted, because it can be measured from a single point. Note that round trip latency excludes the amount of time that a between CPU and the northbridge.
This practice pushes components beyond their specifications and may cause erratic behavior, overheating or premature failure. Even if the computer appears to run normally, problems may appear under a heavy load. Most PCs A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator. This is in contrast to the batch processing or time-sharing models which allowed large expensive mainframe purchased from retailers or manufacturers, such as Hewlett-Packard Hewlett-Packard Company , commonly referred to as HP, is an American multinational information technology corporation headquartered in Palo Alto, California, USA. HP is one of the world's largest information technology companies and operates in nearly every country. HP specializes in developing and manufacturing computing, data storage, and or Dell Dell Inc. is a multinational information technology corporation based in Round Rock, Texas, United States, that develops, sells and supports computers and related products and services. Bearing the name of its founder, Michael Dell, the company is one of the largest technological corporations in the world, employing more than 96,000 people, do not allow the user to change the multiplier or FSB settings due to the probability of erratic behavior or failure. Motherboards purchased separately to build a custom machine are more likely to allow the user to edit the multiplier and FSB settings in the PC's BIOS.
Pros and cons
Pros
Although the front-side bus architecture is an aging technology, it does have the advantage of high flexibility and low cost. There is no theoretical limit to the number of CPUs that can be placed on an FSB, though performance will not scale linearly across additional CPUs (due to the architecture's bandwidth bottleneck A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width of the conduit of exit - that is, bottleneck).
Cons
The front-side bus as it is traditionally known may be disappearing, but it's still being used in all of Intel's Atom Intel Atom is the brand name for a line of ultra-low-voltage x86 and x86-64 CPUs from Intel, designed in 45 nm CMOS and used mainly in netbooks, nettops, and Mobile Internet devices (MIDs). On December 21, 2009, Intel announced the next generation of Atom processors, including the N450, with total kit power consumption down 40%, Celeron, Pentium, and Core 2 processor models. Originally, this bus was a central connecting point for all system devices and the CPU. In recent years, this has been breaking down with the increasing use of individual point-to-point connections like AMD's HyperTransport and Intel's QuickPath Interconnect. The front-side bus has been criticized by AMD as being an old and slow technology that bottlenecks today's computer systems. While a faster CPU can execute individual instructions faster, this is wasted if it cannot fetch instructions and data as fast as it can execute them; when this happens, the CPU must wait for one or more clock cycles until the memory returns its value. Furthermore, a fast CPU can be delayed when it must access other devices attached to the FSB. Thus, a slow FSB can become a bottleneck that slows down a fast CPU. FSB's fastest transfer speed is currently 1.6 GT/s, which provides only 80% of the theoretical bandwidth of a 16-bit HyperTransport 3.0 link as implemented on AM3 Phenom II CPUs, only half of the bandwidth of a 6.4 GT/s QuickPath Interconnect link, and only 25% of the bandwidth of a 32-bit HyperTransport 3.1 link. In addition, in an FSB-based architecture, the memory must be accessed via the FSB. In HT- and QPI-based systems, the memory is accessed independently by means of a memory controller on the CPU itself, freeing bandwidth on the HyperTransport or QPI link for other uses.
Transfer rates
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