The operation of any digital computer depends on the clock frequency, which is determined by the crystal resonator. It is a tin container in which a quartz crystal is placed. Under the influence of an electric voltage, oscillations of the electric current arise in the crystal. This very frequency of oscillation is called the clock frequency. All changes in logic signals in any computer microcircuit occur at regular intervals, which are called clock cycles. Hence, we conclude that the smallest unit of time measurement for most logical devices of a computer is a cycle or, in other words, a period of a clock frequency. Simply put, each operation requires at least one clock cycle (although some modern devices manage to perform several operations in one clock cycle). The clock frequency, as applied to personal computers, is measured in MHz, where Hertz is one oscillation per second, respectively, 1 MHz is a million oscillations per second. Theoretically, if the system bus of your computer operates at a frequency of 100 MHz, then it can perform up to 100,000,000 operations per second. By the way, it is not at all necessary that each component of the system must do something with each clock cycle. There are so-called empty clock cycles (wait cycles) when a device is in the process of waiting for a response from some other device. So, for example, the work of the RAM and the processor (CPU) is organized, the clock frequency of which is much higher than the clock frequency of the RAM.
Bit depth
The bus consists of several channels for transmitting electrical signals. If they say that the bus is thirty-two-bit, then this means that it is capable of transmitting electrical signals on thirty-two channels at the same time. There is one trick here. The fact is that a bus of any declared bit width (8, 16, 32, 64) actually has a larger number of channels. That is, if we take the same thirty-two-bit bus, then 32 channels are allocated to transmit the actual data, and additional channels are designed to transmit specific information.
Baud rate
The name of this parameter speaks for itself. It is calculated using the formula:
clock frequency * bit width = baud rate
Let's calculate the baud rate for a 64-bit system bus operating at a clock frequency of 100 MHz.
100 * 64 = 6400 Mbps 6400/8 = 800 Mbps
But the resulting number is not real. In life, tires are influenced by a bunch of all sorts of factors: ineffective conductivity of materials, interference, design and assembly flaws, and much more. According to some reports, the difference between the theoretical and practical data transfer rate can be up to 25%.
Each bus is monitored by dedicated controllers. They are part of the system logic set ( chipset).
Isa bus
The ISA (Industry Standard Architecture) system bus has been used since the i80286 processor. The expansion slot contains a primary 64-pin and an additional 36-pin connector. The bus is 16-bit, has 24 address lines, provides direct access to 16 MB of RAM. The number of hardware interrupts - 16, DMA channels - 7. It is possible to synchronize the bus and processor with different clock frequencies. The clock frequency is 8 MHz. The maximum data transfer rate is 16 MB / s.
PCI. (Peripheral Component Interconnect bus)
In June 1992, a new standard appeared on the scene - PCI, the parent of which was Intel, or rather the Special Interest Group organized by it. By the beginning of 1993, a modernized PCI variant appeared. In fact, this bus is not local. Let me remind you that the local bus is the bus that is directly connected to the system bus. PCI also uses the Host Bridge to connect to it, as well as the Peer-to-Peer Bridge (peer-to-peer bridge), which is designed to connect two PCI buses. Among other things, PCI is itself a bridge between ISA and the processor bus.
The PCI clock speed can be either 33 MHz or 66 MHz. Bit depth - 32 or 64. Data transfer rate - 132 MB / sec or 264 MB / sec.
The PCI standard provides three types of cards, depending on the power supply:
1.5 Volts - for stationary computers
2.3 Volt - for laptop computers
3. Universal boards that can work in both types of computers.
A big plus for the PCI bus is its Plug and Play compliance. In addition, in the PCI bus, any signaling occurs in a packet manner, where each packet is divided into phases. A packet begins with an address phase, usually followed by one or more data phases. The number of data phases in a packet can be undefined, but is limited by a timer that determines the maximum time that a device can be used on the bus. Each connected device has such a timer, and its value can be set during configuration. An arbiter is used to organize the work on data transmission. The fact is that there can be two types of devices on the bus - the master (initiator, master, master) of the bus and the slave. The master takes over control of the bus and initiates the transfer of data to the destination, i.e. the slave. Any device connected to the bus can be a master or slave, and this hierarchy is constantly changing depending on which device has requested permission from the bus arbiter to transfer data and to whom. The chipset, or rather the North Bridge, is responsible for the conflict-free operation of the PCI bus. But life on PCI has not stopped its course. The constant improvement of video cards led to the fact that the physical parameters of the PCI bus began to be insufficient, which led to the emergence of AGP.
CPU performance is dependent on bit depth, frequency, and processor architecture. The operation of the computer as a whole depends on this integral value, which means that when choosing, you will have to pay attention to all the characteristics of the processor. The processor must have sufficient performance for solving certain tasks.
Processor manufacturers
There are two large, leading manufacturers in the processor market: Intel and AMD. Processor specifications vary from manufacturer to manufacturer. Much depends on the perfection of technology, materials used, layout and other nuances.
CPU clock speed
Clock speed indicates the speed of the processor in Hertz (GHz) - the number of operations per second. The processor clock speed is subdivided into internal and external. Yes, this characteristic of the processor significantly affects the speed of your PC, but performance depends not only on it.
- The internal clock rate refers to the rate at which the processor processes internal instructions. The higher the value, the faster the external clock speed.
- The external clock speed determines how fast the processor accesses the RAM.
Processor size
The bit width is the limiting number of bits of a binary number, over which a machine operation of information transfer can be performed at a time. The higher the bit depth, the higher the processor performance. Nowadays most processors are 64-bit and support 4 gigabytes of RAM. This is one of the main characteristics of the processor, but far from the only one; when choosing, you need to be guided not only by it.
Dimension of the technological process
Determines the dimensions of the transistor (thickness and length of the gate). The frequency of the crystal is determined by the switching frequency of the transistors (from closed to open state). If the size is smaller, then the area is smaller, and hence the generation of heat. The dimension of the technological process is measured in nanometers, the lower this indicator, the better.
Socket or connector
A female or slotted connector designed to integrate the CPU chip into the motherboard circuitry. Each socket only allows the installation of a certain type of processor, check the socket of the selected processor with your motherboard, it must match it.
Female connector type:
- PGA (Pin Grid Array) - square or rectangular case, pin contacts.
- BGA ( BallGrid Array) - solder balls.
- LGA (Land Grid Array) - contact pads.
Processor cache
The processor cache is one of the key characteristics to look out for when choosing. Cache memory is an array of ultra-fast volatile RAM. It is a buffer that stores data with which the processor interacts more often or interacted during the last operations. This reduces the number of processor accesses to the main memory. This type of memory is divided into three levels: L1, L2, L3. Each of the levels is different in memory size and speed, and their acceleration tasks are different. L1 is the smallest and fastest, L3 is the largest and slowest. The larger the cache, the better. The processor accesses each level in turn (from the lowest to the highest) until it finds the necessary information in one of them. If nothing is found, it accesses the RAM.
Power consumption and heat dissipation
The higher the power consumption of the processor, the higher its heat dissipation. Adequate cooling must be ensured.
TDP (Thermal Design Power) is a parameter indicating the amount of heat that a cooling system can take away from a particular processor under the greatest load. The value is expressed in watts at the maximum temperature of the processor case.
ACP (Average CPU Power) - Average processor power, showing the power consumption of the processor for specific tasks.
In practice, the value of the ACP parameter is always lower than the TDP.
Processor operating temperature
The highest indicator of the processor surface temperature at which normal operation is possible (54-100 ° C). This indicator depends on the load on the processor and on the quality of heat dissipation. If the limit is exceeded, the computer will either reboot or simply shut down. This is a very important characteristic of the processor, which directly affects the choice of the type of cooling.
Multiplier and system bus
These parameters are necessary rather for those who, over time, plan to disperse their stone. Front Side Bus - frequency of the system bus of the motherboard. The processor clock speed is the product of the FSB frequency by the processor multiplier. Most processors have multiplier overclocking disabled, so you have to overclock on the bus. It is worth familiarizing yourself with this characteristic of the processor in more detail, if after a certain period of time you want to increase the performance in software, without upgrading the hardware.
Integrated graphics
The processor can be equipped with a graphics core, which is responsible for displaying images on your monitor. In recent years, built-in video cards of this kind have been well optimized and run the main software package and most games at medium or minimum settings without any problems. For work in office applications and surfing the Internet, watching Full HD video and playing at medium settings, such a video card is quite enough, and this is Intel.
As for AMD processors, their integrated GPUs are more powerful, which makes AMD processors a priority for gamers looking to save money on the purchase of a discrete graphics card.
Number of cores (threads)
Multi-core is one of the most important characteristics of a CPU, but it has received too much attention lately. Yes, now we need to try to find working single-core processors, they have outlived their usefulness. The single-core processors were replaced by processors with 2, 4 and 8 cores.
If 2 and 4-cores came into use very quickly, processors with 8 cores are not yet so in demand. To use office applications and surf the Internet, 2 cores are enough, 4 cores are required for CAD and graphics applications that just need to work in multiple threads.
As for 8 cores, very few programs support so many threads, which means that such a processor is simply useless for most applications. Usually, the fewer threads, the higher the clock speed. It follows from this that if a program adapted for 4 cores, and not for 8, it will run slower on an 8-core process. But this processor is an excellent solution for those who need to work simultaneously in a large number of demanding programs at the same time. By evenly distributing the load across the processor cores, you can enjoy excellent performance in all the programs you need.
In most processors, the number of physical cores corresponds to the number of threads: 8 cores - 8 threads. But there are processors where, thanks to Hyper-Threading, for example, a 4-core processor can process 8 threads simultaneously.
Conclusion
From the article you learned about the existing characteristics of central processors, now you know what to look for when choosing. If the information in the article is no longer relevant, let us know in the comments, then we will update or supplement the information in the article.
When you buy or assemble a desktop computer, you can find out that one of the most expensive parts will be the processor. A processor is an electronic unit or circuit that executes machine instructions and is also one of the main pieces of hardware in a computer.
The processor has many different parameters, one of which is called the clock speed. What it is?
The processor clock frequency is the frequency of the clock pulses of the synchronous electronic circuit, which are sent from the outside to the input of the circuit in one second. In other words, this is the number of operations performed by the processor in one second. At the same time, it is important not to forget that processors with the same clock frequency can have different performance, therefore, different systems require a different number of clock cycles to perform one operation.
Clock frequency is measured in frequency units - megahertz and gigahertz.
It is believed that the higher the value, the more efficient the processor itself. This is partly true, but only for models in the same manufacturer's lineup. After all, processor performance is also influenced by other characteristics, for example, bus frequency or cache size. Some manufacturers allow "overclocking" the processor clock speed.
By the way, an interesting point. As you know, single-core processors are not so common today; they have been replaced by multi-core processors. However, this is not surprising, but this is not the point. Many people ask how the clock speed of multi-core processors is calculated? Some users believe that it is sufficient to multiply the clock speed by the number of processor cores. That is, if an 8-core processor has a frequency of 3GHz, then you need to multiply 8 by 3 and we get a frequency of as much as 24 GHz. In fact, this calculation has nothing to do with reality.
To understand the very principle of calculating the clock frequency, you need to consider a simple example. Let's say we have a car that develops 200 km per hour (that is, a single-core processor). If we take 4 such cars (4-core processor), then no matter how hard we push, we will not be able to accelerate these cars to a speed of 800 km per hour at any desire. So it is with a clock frequency - if it is 3 GHz, then a 4-core processor has a frequency of the same 3 GHz.
Of all the technical characteristics of the processor, the most famous among users is the clock frequency. But, few of the non-specialists fully understand what it is. More information on this will help you better understand how computing systems work. Especially when using multi-core processors that have certain operating features that are far from known to everyone, but which should be taken into account when operating a computer.
For a long time, the main efforts of developers were directed precisely at increasing the clock frequency. Only recently there has been a tendency for the development and improvement of computer architecture, an increase in the amount of cache memory, the number of processor cores. However, the clock frequency of the processor is not ignored either.
What is this parameter - the clock speed of the processor?
Let's try to figure out what a "processor clock speed" is. This value characterizes the number of calculations that the processor can perform in one second. Consequently, a processor with a higher clock speed also has a higher performance, i. E. is able to perform more operations in a certain period of time.
Most modern processors are clocked at 1 GHz to 4 GHz. This value is defined as the product of the base frequency and a certain coefficient. In particular the processor Intel Core i7 920 has its own clock frequency of 2660 Hz, which is obtained due to the base bus frequency of 133 MHz and a factor of 20. Some manufacturers produce processors that can overclock to higher performance. For example, AMD's Black Edition and Intel's K-series lineup. It should be noted that, despite the importance of this characteristic, it is not decisive when choosing a computer. The clock speed only partially affects the performance of the processor.
Single-core processors have practically sunk into oblivion, and are rarely used in modern computing devices. This is due to the development of the IT industry, the progress of which never ceases to amaze. Even experts sometimes have an erroneous opinion on how to calculate the clock speed of a processor with two or more cores. A common misconception is that the clock speed must be multiplied by the number of cores. For example, a 4-core processor running at 3 GHz will have an integrated frequency of 12 GHz, i.e. 4x3 = 12. But this is not true.
Let's explain this with a simple example.... Take a pedestrian walking at 4 km / h - it's a 4 GHz single-core processor. And a 4-core processor with a clock of 4 GHz is already 4 pedestrians walking at the same speed of 4 km / h. Indeed, in this case, the speed of pedestrians is not summed up, and we cannot say that they are moving at a speed of 16 km / h. We're just talking about four pedestrians walking together at 4 km / h each. The same analogy applies to a multi-core processor. Thus, we can say that a 4-core processor with a clock speed of 4 GHz simply has four cores, each of which has the same frequency - 4 GHz. From this follows a simple and logical conclusion, the number of processor cores affects only its performance, and does not increase the total clock frequency of the computing device.
Clock frequency is called a parameter that is measured in gigahertz. A higher clock rate allows faster data processing. This is one of the most important parameters that you should pay attention to when choosing a processor.
The number of cores is no less important, the fact is that the clock frequency at this stage of development can no longer be increased, this prompted the continuation of development in the direction of parallel computing, expressed in an increase in the number of cores. The number of cores informs about how many programs can be run simultaneously without losing performance. However, it should be borne in mind that if the program is optimized for two cores, then even if there are more of them, the computer will not be able to fully use them.
Processor Cache and Bus Frequency
The bus frequency demonstrates the transfer rate of information entering and leaving the processor. The higher this indicator, the faster the exchange of information is, the units of measurement here are gigahertz. Of great importance is the processor's cache, which is a high-speed block of memory. It is located directly on the core and serves to improve performance, since data is processed in it at a much higher speed than in the case of RAM. There are three levels of cache memory:
L1 - the first level is the smallest in size, but the fastest, its size varies from 8 to 128 KB.
L2 is the second level, much slower than the first, but exceeds it in volume, here the size varies within the range of 128 - 12288 KB.
L3 is the third level, loses in speed to the first two levels, but the most voluminous, by the way, it may be absent altogether, as it is provided for special editions of processors or server solutions. Its size reaches 16384 KB, it can be present in such processors as Xeon MP, Pentium 4 Extreme Edition or Itanium 2.
Socket and heat dissipation
Less significant, but not losing their relevance when choosing a processor are such characteristics as the socket and heat dissipation. Socket called the connector where the processor is installed in the motherboard. By indicators heat release you can determine the degree of heating of the processor during operation. This indicator is measured in watts, and it varies between 10 - 165W.
The average cost of processors in the Moscow market is Intel Core 2 Duo 5000 rubles, and AMD Athlon X2 Dual-Core 3000 rubles, according to http://price.ru
Tab. 3 Comparison of processors
To work with graphics, the frequency of the bus and the processor is important, therefore, in accordance with the minimum hardware requirements when choosing between the two offered CPUs, relying on the above key characteristics, as well as on the price qualities, I prefer the AMD ATHLON II X2 CPU http://www.nix.ru .
