Why are CPU ARM and X86 so bad?

Yesterday, I was asked about Xiaobian Xiaolong 835's Win instinct? Also want to understand where the difference between the mobile phone CPU and the computer CPU. This problem is actually very interesting, because unlike in the past, with the mobile phone CPU toward multi-core development, the computing performance itself is also very prominent, no wonder that many people are discussing this issue. Xiaobian said today that the difference between the two, do not look called CPU, genetically they are still a lot worse.

We are not the same

Although they are called CPUs, they are essentially different - the core difference is the architecture. Usually we talk about the computer's CPU, are based on the X86, X64 architecture; mobile phone CPUs are now all ARM architecture, the two architecture from the design point of departure is not the same, but it also involves a core problem: instruction set.

The instruction set used by the computer CPU is called CISC, which means "Complex Instruction Set Computer". The instruction system of the CISC instruction set is very rich, and the commands are usually very complicated, so that the instructions issued by the operation are also targeted. Execution efficiency is higher; CPU of ARM framework uses RISC, meaning "reduced instruction set computer", its characteristic is to optimize for commonly used commands, let him give a more concise execution environment. At the same time, functions that are not commonly used are combined by various simplification instructions.

Simply put, it is the X86/X64 computer CPU is more suitable for a complex operating environment, and ARM's mobile phone CPU is suitable for the implementation of targeted use of the environment. Obviously, fundamentally, the starting point of the two is not the same. The former pursues a large scale and the latter pursues smallness and precision.

Why ARM CPU can go up one step every year, computer CPU upgrade is so slow? Fundamentally speaking, the RISC CPU has a simple structure, a compact layout, and even a modular design. The design cycle is shorter and easier to use the latest technology. In contrast, the CISC CPU has a longer design cycle because of the complex structure, and fundamentally, computers. The CPU does not yet have a modular design like the ARM CPU.

Can alternative relationships be implemented?

However, with the development of time, the ARM architecture CPU's flexible architecture allows it to quickly iterate, the performance is also a leap forward, and even some tests have the ability to rival the X86/X64 CPU. But is this alternative? The answer is certainly not.

In Xiao Bian's view, ARM-based CPUs are more likely to emerge as complementers than as replacements. It can be said that for a period of time from the present and even the visible future, the powerful performance of the computer CPU is that the mobile phone CPU cannot be replaced, because the complicated use demand is various, and the mobile phone CPU still belongs to the specialized computing function rather than the full-scale hand. .

For example, mobile phones support 4K high-definition decoding is not too power-consuming. This is because special algorithms are optimized and hardware adjustments are implemented. In other words, what specific functions are needed for the key functions, the mobile CPU can be targeted. Sexual adjustments, computer CPUs are less capable in this regard, after all, it is the pursuit of versatility, to take care of all functional requirements.

So you can see that Xiao Long 835's notebook is compatible with the Windows EXE application (Microsoft and Qualcomm cooperation, targeted optimization), but the product has not really listed, waiting until the simulation compatibility is fully mature, that is, Xiao Long This product will only appear when the 845. Moreover, they are mainly aimed at ultra-thin and ultra-portable notebook market, in the performance of products that are still on the computer CPU products, this will not change.