Clock and L2 cache, what is the difference between clock frequency and cache?

L2 caching is more important.

The main frequency refers to the clock frequency of the CPU, theoretically speaking, the larger the main frequency, the faster, in fact, this is not the case, and it will be affected by many factors.

The previous processor was very particular about the main frequency, such as: AMD poison dragon Celestial Sailing Pentium four, etc., but later, AMD processors began to use the main frequency as a model, such as: Athlon 1500+, Sempemptosaurus 2500+, Barton 3200+, etc., Intel in 478 Ben Four, from the beginning of Celeron D to cancel the use of the main frequency as a model, such as:

Celeron D347, Celeron E1200, Pentium E2220 and so on.

You may still remember that as early as 7 years ago or so, the very popular 478-pin Pentium four computer, the highest frequency of the Pentium four at that time was about the same, if you take the Pentium four and the Core 2 quad Q8200

Pentium IV: main frequency, L2 cache 512KB

Quad Q8200: Main frequency: , L2 cache: 4096KB

Nowadays, the main frequency of quad Q8200 is not as good as the early Pentium Four, but the second-level cache is many times higher than that of Pentium Four, with Quad Q8200 now ** is about 1000 yuan, and the 478-pin Pentium 4 has been discontinued.

This probably also shows that the main frequency is not the mainstream factor today.

The above content is purely personal and in no way plagiarized.

To judge the quality of a CPU, you can't simply look at the main frequency, nor can you simply look at the second-level cache.

There is a premise for judging the quality of a CPU by looking at the main frequency, the premise is: when the core of the two CPUs is the same, the architecture is the same, the process is the same, and the L2 cache is the same, the same series of CPUs can be judged by the main frequency, for example, the main frequency of E7400 is higher than that of E7300, and the performance of E7400 is slightly better.

Judge the quality of the CPU:

1. Looking at the number of CPU cores, the current mainstream is dual-core, single-core (such as Pentium 4) has long been discontinued, and the high-end has quad-core.

2. Looking at the production process, the current 45nm CPU has been popularized, the previous generation is 65nm, and the older 90nm (rare). The manufacturing process of 45 nanometers refers to the width of the wire connection between the transistor and the transistor (referred to as the line width), which simply means that it can be on the chip in the same area"Squeeze"More transistors, more transistors leads to higher performance. Even if the number of transistors does not increase, the area of the chip can be reduced accordingly, so that the power consumption and temperature can be reduced by a lot.

3. Look at the size of the L2 cache, the CPU is in the computer"Run"Sometimes, because it runs too fast, other hardware such as memory can't keep up with it, so CPU manufacturers have introduced caches. Judging the quality of the CPU by looking at the size of the second-level cache is mainly for Intel's CPU, because Intel's CPU relies heavily on the second-level cache, Intel's CPU second-level cache is mainly used to store data, and the first-level cache stores the address of the second-level cache, and these data are numbered such as a-z in the first-level cache, and the CPU needs to retrieve the data directly from the first-level cache when the number of the data is retrieved, for example, For example, the L2 cache is the content of a book, and the L1 cache is the directory of the book, which is why Intel's CPU L2 cache is particularly large, while the L1 cache is particularly small. AMD's CPU design is different from Intel's, AMD's CPU Level 1 cache is used to store the most commonly used data, and the Level 2 cache is used to store more commonly used data, so AMD's CPU Level 1 cache and Level 2 cache are about the same size.

Theoretically, Intel's CPU is more efficient, and the CPU can directly retrieve the number when it needs to retrieve some data.

4. The main frequency, in the case that the first three are the same, the quality of the CPU can be judged by the level of the main frequency, most of the CPU main frequency is around the to, and the highest is not exceeded, because the higher the main frequency, the greater the heat and power consumption, and the main frequency is too high, there will be more drawbacks, so there is no CPU frequency exceeded.

The higher the clock speed, the faster the CPU processing speed, and the L2 cache acts as a scratching data, which is much faster than memory, so it is installed directly in the CPU to reduce the time it takes to read data from memory.

The higher the main screen, the larger the L2 cache, the faster the processing speed, you don't actually have to choose anything, because the manufacturer will reasonably configure the main frequency and L2 cache.

You just need to pay attention to the main frequency, and the second-level cache is a small point.

L2 caching is important, but cores are even more important.

Main frequency: The main frequency is also called the clock frequency, the unit is Hz, which is used to indicate the computing speed of the CPU.

Cache: Cache memory is a temporary memory between the CPU and memory, which is smaller than memory but swaps faster.

The main frequency, that is, the clock frequency of the CPU, is the working frequency of the CPU. Generally speaking, the number of instructions completed in a clock cycle is fixed, so the higher the frequency, the faster the CPU. However, due to the different internal structures of various CPUs, the performance of CPUs cannot be completely summarized by the main frequency.

As for the external frequency, it is the operating frequency of the system bus; The frequency doubling refers to the multiple of the difference between the CPU external frequency and the main frequency. It is expressed by the formula: main frequency = external frequency and frequency doubling.

The principle of caching is that when the CPU wants to read a data, it will first look it up from the cache, and if it finds it, it will read it immediately and send it to the CPU for processing; If it is not found, it is read from the memory at a relatively slow speed and sent to the CPU for processing, and at the same time, the data block where the data is located is called into the cache, so that the entire block of data can be read from the cache in the future, and the memory does not need to be called. It is this read mechanism that makes the CPU read cache hit rate very high (most CPUs can reach about 90%), which means that 90% of the data that the CPU will read next time is in the cache, and only about 10% needs to be read from memory. This greatly saves the CPU time to read the memory directly, and also makes the CPU almost free to wait when reading data.

In general, the order in which the CPU reads data is cached first and then memory.

1。The main frequency is also called the clock frequency, and the unit is Hz, which is used to indicate the computing speed of the CPU. It determines the speed of the computer, with the development of the computer, in the same series of microprocessors, the higher the frequency, the faster the speed of the computer, but for different types of processors, it can only be used as a parameter for reference.

In addition, the computing speed of the CPU also depends on the performance indicators of all aspects of the CPU pipeline. Since the main frequency does not directly represent the computing speed, in some cases, it is likely that the actual computing speed of the CPU with a higher frequency will be lower. Therefore, the clock speed is only one aspect of CPU performance, and does not represent the overall performance of the CPU.

2。The cache is the buffer (called the cache) for data exchange, when a piece of hardware wants to read data, it will first find the data it needs from the cache, if it is found, it will be executed directly, and if it cannot be found, it will be found from memory. Because caching runs much faster than memory, the purpose of caching is to help the hardware run faster.

Because caches often use RAM (non-permanent storage that is lost when the power is off), files are still sent to hard disks and other storage for permanent storage after they are used up. The largest cache in the computer is the memory module, the fastest is the L1, L2, L3 cache embedded in the CPU, the video memory of the graphics card is the cache for the graphics card computing chip, and the hard disk also has 16M or 32M cache.

Let me talk about the difference between BIOS and CMOS, the upstairs copy such a large paragraph, and the people who watch it are dizzy.

To put it simply, it's the difference between hardware and software!

BIOS: There is an integrated block (hardware) on the motherboard that is the BIOS chip, which is generally around the motherboard battery, usually near the south bridge. There is a program stored in the BIOS, and when the computer is booted, the motherboard will be checked by the program that comes with the BIOS to check whether the motherboard is normal and whether the hardware is damaged; There is a program in the BIOS that allows the user to change the settings, and this is the CMOS.

CMOS: After the program of the BIOS has detected the motherboard, CPU, memory, graphics card, hard disk, etc., you can press del or F2 (depending on the motherboard) to enter the CMOS setting interface. You can adjust the motherboard's functions, such as overclocking, boot order, etc.; Once set up and saved, there will be a corresponding program module to save your changes; When the computer loses power, the changes you make will be powered by the motherboard's battery to keep the changes from disappearing.

When you modify the content, such as time, boot order, always restore to the factory state, and may prompt you to press F1 to continue, it may be that the motherboard battery is dead (there will be a prompt that the battery is low); It is also possible that the current output of the motherboard battery is insufficient (no prompt, just replace the battery with a new one, it will be no problem); It may also be that the two diodes of D1 and D2 are broken (replaced); If none of the above is true, it may be that the IC chip of the BIOS itself is broken, or there may be a problem with the South Bridge; If it is a south bridge, it is more complicated, and BGA equipment is used to repair it, but some old motherboards have no repair value, only discarded.