Server processor Parameters

1. Server processor clock speed

The clock speed of the server processor is also called the clock frequency. The unit is MHz, which indicates the computing speed of the CPU. CPU clock speed = frequency X frequency doubling coefficient. Many people think that the clock speed determines the CPU running speed. This is not only one-sided, but also a misunderstanding of the server. So far, there is no definite formula for realizing the numerical relationship between the clock speed and the actual computing speed. Even two major processor manufacturers, Intel and AMD, are still very controversial, we can see from the development trend of Intel products that intel is very focused on strengthening its clock speed. Like other processor manufacturers, some once compared to daliyun.com, which is equivalent to 2 GB intel processor.

Therefore, there is no direct relationship between the CPU clock speed and the actual computing power of the CPU, and the clock speed represents the speed at which the digital pulse signals in the CPU oscillate. In Intel's processor products, we can also see the example that the 1 GHz itanium chip can behave almost as fast as the 2.66 GHz Xeon/opteron chip, or 1.5 GHz itanium 2 is about as fast as 4 GHz Xeon/opteron. The computing speed of the CPU depends on the performance indicators of the CPU pipeline.

Of course, the clock speed is related to the actual computing speed. It can only be said that the clock speed is only one aspect of the CPU performance, not the overall performance of the CPU.

2. Server Front-End bus (FSB) frequency

The front-end bus (FSB) frequency (that is, the bus frequency) directly affects the direct data exchange speed between the CPU and memory. There is a formula that can be calculated, that is, data bandwidth = (bus frequency × data bandwidth)/8. The maximum bandwidth of data transmission depends on the width and transmission frequency of all data transmitted simultaneously. For example, the current 64-bit Xeon Nocona is supported, and the frontend bus is 800 MHz. According to the formula, its maximum bandwidth for data transmission is 6.4 GB/second.

The difference between the external frequency and the FSB frequency: the speed of the front-end bus refers to the speed of data transmission, and the external frequency is the speed of synchronous operation between the CPU and the motherboard. That is to say, a 10 million MHz external frequency refers to a digital pulse signal that oscillates times per second; the 800 MHz Front-End bus refers to the amount of data transmitted per second that the CPU can accept is MHz × 64bit bytes 8byte/bit = Mb/s.

In fact, the emergence of the "hypertransport" architecture has actually changed the frequency of the front-end bus (FSB. We know that IA-32 architecture must have three major components: Memory Controller Hub (MCH), I/O controller hub and PCI hub, like Intel's typical chipset intel 7501, intel7505 chipset, designed for dual Xeon processors, the MCH provided a 533mhz Front-End bus for the CPU. In combination with the DDR memory, the front-end bus bandwidth can reach 4.3 GB/second.

However, as the processor performance continues to improve, it also brings many problems to the system architecture. The "hypertransport" architecture not only solves the problem, but also improves the bus bandwidth more effectively. For example, the amd opteron processor, the flexible hypertransport I/O bus architecture enables it to integrate the memory controller, enable the processor to directly exchange data with the memory without passing through the system bus to the chipset. In this case, the front-end bus (FSB) frequency is unknown in the amd opteron processor.

3. processor external frequency

The external frequency is the baseline frequency of the CPU, and the Unit is MHz. The external frequency of the CPU determines the running speed of the entire motherboard. To put it bluntly, in desktops, The overclock we call is the extra frequency of the Super CPU (of course, the frequency doubling of the CPU is usually locked). I believe this is a good understanding. However, for the server CPU, overclocking is absolutely not allowed. As mentioned above, the CPU determines the running speed of the motherboard. The two operations are synchronous. If the CPU of the server is too frequently and the external frequency is changed, asynchronous operation will be generated, (Many desktops support asynchronous operation on the motherboard) This will cause instability of the entire server system.

In most computer systems, the external frequency is also the speed of synchronous operation between the memory and the motherboard. In this way, it can be understood that the external frequency of the CPU is directly connected to the memory, synchronous running status between the two. The external frequency and the FSB frequency are easily confused. The following section describes the differences between the front-end bus and FSB.

4. CPU bit and Word Length

Bit: binary is used in digital circuits and computer technologies. The code is only "0" and "1 ", either "0" or "1" is a "bit" in the CPU ".

Word Length: in computer technology, the number of digits of the binary number that the CPU can process at a time in a unit of time (at the same time) is called the word length. Therefore, an 8-bit CPU can process 8-bit data. Similarly, a 32-bit CPU can process 32-bit binary data per unit time. The difference between byte and Word Length: because common English characters can be expressed in 8-bit binary, 8-bit is usually called a byte. The length of the word length is not fixed, and the length of the word length varies with the CPU and the word length. The 8-bit CPU can only process one byte at a time, while the 32-bit CPU can process four bytes at a time. A 64-bit CPU can process eight bytes at a time.

5. multiplier Coefficient

The multiplier refers to the relative proportional relationship between the CPU clock speed and the external frequency. The higher the frequency, the higher the CPU frequency. But in fact, with the same external frequency, the CPU itself has little significance. This is because the data transmission speed between the CPU and the system is limited, when a CPU with a high frequency is pursued, a significant "bottleneck" effect will occur-the speed at which the CPU obtains data from the system cannot meet the CPU operation speed. Generally, Intel's CPU except for the engineering sample version locks the frequency doubling, but amd never locks.