The CPU processor term interprets the outer frequency of the CPU and even the entire computer system, and the unit is MHz (megaz). In an earlier computer, the speed of the synchronous operation between memory and motherboard is equal to the outer frequency, in which case the CPU is directly connected to the memory, and the synchronous operation state between the two is realized. For the current computer system, the two can be completely different, but the significance of the outer frequency still exists. Most of the frequencies in the computer system are based on the outer frequency, and multiplied by a certain number of times. This multiple can be More than 1, may also be less than 1.
Speaking of the processor's external frequency, it is necessary to mention two concepts associated with it: multiplier and the frequency, the frequency is the clock frequency of the CPU; the multiplication of frequency and the ratio of the frequency and the overall frequency. Main frequency, outer frequency, frequency, its relationship: the main frequency = Overseofree × multiplier.
Prior to 486, the CPU's frequency is still in a lower stage, and the CPU's climb is generally equal to the outer frequency. After 486, since the CPU operating frequency is increasing, some of the other devices of the PC (such as card, hard disk, etc.) are limited by the process, and the higher frequency cannot be subjected to a higher frequency, so that the CPU frequency is further improved. Therefore, a multiplier technology can occur, which enables the CPU internal operating frequency to become a multiple of the external frequency, thereby reaching the purpose of lifting the frequency through lifting multiplier. The multiplier technology is that the external device can work on a lower outer frequency, while the CPU cluster is a multiplication of the outer frequency.
In the Pentium era, the outer frequency of the CPU is generally 60 / 66MHz, starting from Pentium II 350, the CPU has increased to 100MHz, and the current CPU has reached 200MHz. Since the frequency of the outer frequency and memory bus is the same, the exchange rate between the memory is also improved after the CPU is increased, and the exchange rate between the memory is also improved, and the overall operation speed of the computer is greater.
Frequency Frequency and Front End Bus (FSB) frequencies are easily mixed. The speed of the front-end bus refers to the speed of the CPU and the North Bridge chip bus, and more substantially represents the speed of the CPU and the external data transmission. The concept of foreign frequency is based on the oscillation speed of digital pulse signals, that is, 100MHz external frequency index pulse signal is shocked by 10,000 times per second, and it has more affected PIC and other buss. Frequency of. The reason why the front-end bus and the outer frequency is easily confused, the main reason is that in the previous period (mainly before Pentium 4 appears and just Pentium 4), the front-end bus frequency is the same. Therefore, it is often called the front-end bus as an outer frequency, and eventually causes such a misunderstanding. With the development of computer technology, people have found that the front-end bus frequency needs higher than the outer frequency, so the QDR (Quad Date Rate) technology is used, or other similar technologies is implemented. The principles of these technologies are similar to the AGP 2x or 4x, which makes the frequency of the front-end bus into the outer frequency, 4 times or even higher, since then, the distal end bus and the cross-frequency difference began to pay attention to it.
