The cpu is the core component of the computer, and even Xiaobai should know something. However, many white people don't know how to treat cpu and how to choose the appropriate cpu model when actually buying and assembling computers.
Let's talk about some important parameters of the cpu first: (The following CPU parameters can be skipped directly if you look hard, see the end of the article)
1, main frequency
The clock frequency inside the CPU is the working frequency when the CPU performs operations. Generally speaking, the higher the main frequency, the more instructions completed in a clock cycle, and the faster the CPU runs. However, due to different internal structures, not all CPUs with the same clock frequency have the same performance.
2. External frequency
That is, the system bus, the frequency of data transmission between CPU and peripheral devices, specifically the bus speed between CPU and chipset.
3. Frequency doubling
There is no concept of frequency doubling. The main frequency of CPU is the same as the speed of system bus, but the speed of CPU is getting faster and faster, and the frequency doubling technology was born. The system bus can work at a relatively low frequency, and the CPU speed can be infinitely improved by frequency doubling. Then the calculation method of CPU main frequency becomes: main frequency = external frequency x frequency doubling. In other words, frequency doubling refers to the multiple of the difference between CPU and system bus. When the external frequency is constant, the higher the frequency multiplication, the higher the CPU frequency. K version of Intel CPU can be overclocked by adjusting frequency doubling and voltage.
4. Hidden objects
Most data information processed by CPU is retrieved from memory, but the operation speed of CPU is much faster than that of memory. So in this transmission process, a memory is placed to store data and instructions frequently used by CPU. This can improve the data transmission speed. It can be divided into primary cache, secondary cache, and some have tertiary cache.
5. Level 1 cache
That is, L 1 cache. It is integrated in the CPU and used to temporarily store data while the CPU is processing data. Because the working frequency of cache instructions and data is the same as that of CPU, the larger the cache capacity of L 1 level, the more information is stored, which can reduce the number of data exchanges between CPU and memory and improve the running efficiency of CPU. However, cache memories are all composed of static RAM, and their structures are complex. In the limited CPU chip area, the capacity of L 1 level cache cannot be made too large.
6. Secondary cache
That's the L2 cache. Due to the limitation of L 1 level cache capacity, in order to improve the operation speed of CPU again, a high-speed memory, namely the secondary cache, is placed outside the CPU. The main working frequency is flexible, which can be the same as or different from the CPU. When the CPU reads data, it first looks in L 1, then in L2, then in internal memory, and then in external memory. Therefore, the influence of L2 on the system can not be ignored.
7. Three-level cache
The third-level cache is designed for reading the data that miss after the second-level cache. In a three-level cache CPU, only about 5% of data needs to be called from the memory, which further improves the efficiency of the CPU. Its working principle is to use a faster storage device to save a copy of the data read from a slower storage device and copy it. When you need to read and write data from slow storage, caching can make the reading and writing actions be completed on faster devices first, which will make the system respond faster.
7、TDP
The CPU is fully loaded with maximum power.
9, manufacturing process
The manufacturing process of CPU refers to the width of connecting wires of internal components when producing CPU on silicon material. It used to be expressed in microns, but now it is mostly expressed in nanometers. The smaller the value, the more advanced the manufacturing process, the higher the frequency that the CPU can achieve, the lower the power consumption, and the more transistors that can be integrated. At present, Intel's manufacturing process is 14 nm, and AMD is 28nm.
Simply put, the larger the main frequency and cache of products on the same platform, the better, and the power consumption is directly proportional to the calorific value. Generally speaking, the higher the TDP, the more expensive the radiator.
Next, I will talk about some problems that Xiaobai needs to pay attention to when choosing CPU.
1, the more cpu cores, the better?
In Xiao Bai's view, the more cores there are in the cpu, the better the performance. So many JS seize this point to fool Xiaobai.
The price of dual-core i3 4 170 is around 750, and the price of quad-core AMD 860K is less than that of 400 yuan. In terms of performance, i3 4 170 is much higher than AMD 860K. Which CPU is better, dual-core I34 or quad-core 860K? Interested friends can look at another article on this site, "What's the difference between dual-core and quad-core? Dual-core or quad-core? ”》
2.CPU is divided into boxes and chips. What's the difference between them?
In fact, there are three kinds of CPU on the market now: original box, turned box and bulk. The original box CPU refers to the box CPU equipped with the original fan, which enjoys the conventional three-year warranty. Turning over the package is to add inferior fans and packaging to bulk or OEM CPU, so as to pretend to be boxed and earn high price difference. In addition to the one-year warranty, the bulk CPU is not equipped with a fan, but the price is much cheaper, and the performance is no different from that of the boxed CPU. It is the first user to pay attention to cost performance. Consumers must keep their eyes open when buying, and don't spend money to buy boxed cpu but flip cpu.
3, the same is i5, i7, the product performance of different times is very different.
Many users don't know how to assemble computers casually, but they often hear words like Core, i3, i5 and i7 from the crowd. This is also what JS likes to use. Intel Core series processors have been developed to the sixth generation. At present, only the fourth and sixth generation products are normally sold in the market, and the third generation products are also sold in small quantities (mostly due to inventory backlog). The first and second generations have been discontinued for a long time. Some unscrupulous manufacturers will fool Xiaobai with outdated products, and I often meet Xiaobai with such a configuration sheet to consult. As shown in the figure:
In Xiao Bai's view, this configuration list seems to be a bargain for himself. You can buy an i5 at such a low price. Actually, this i5 is different from the others. In the picture, this i5 is the best in 300 yuan, while the latest 6th generation i5 is about 1300 yuan. I won't say much about other accessories here, they are all covered by small white pits.
4. Is it Intel or AMD?
At present, there are only two choices for home computer processors, Intel and AMD. There is no need to entangle the low-end price host. Choose what you like. Generally speaking, AMD will have a higher cost performance. If the price is in the middle and high end, it is recommended to choose Intel, because AMD really didn't get the middle and high end products. This is really not in black AMD. A ladder diagram of CPU performance can draw a clear conclusion.