CPU-Table of Contents Topic Table of Contents Introduction to the Processor (CPU) CPU Basics CPU Processing CPU Enhancements What Happens to Instructions, Step by Step CPU History MHz Myth Shorter Pipeline Pipeline Tax Page 1 2 3 4 5 6 7-8 9 9 10
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Introduction tothe Processor (CPU)
Many people consider the CPU (Central Processing Unit) to be the brains of the computer. This analogy is very loose because, for the most part, the CPU cannot keep data stored inside it like a brain. In contrast, it is used to process much of the information needed by the computer, just like our brain thinks and processes information and gives orders to our other body parts.Intel's Next generation processor, the Itanium, featuring 64-bit architecture. © Intel Corp, 2001 Over the past few years, we have seen the CPU MHz speeds go from 100 MHz to over 2 GHz (1000 MHz = 1 GHz). This is one reason that people need to learn about a CPU. Many people would expect a 1.8 GHz Intel Pentium 4 to be much faster than a 1.4 GHz AMD Athlon because its speed is 0.4 GHz faster. Intruth, not only is the Intel Pentium 4 up to three times more expensive than the AMD Athlon, it is either much slower or neck to neck in most "Real world tests", which compares the amount of times that it takes each CPU to perform a certain task. With this information, you know that you should not judge a computer by the "speed ratings". But if one CPU goes at a faster MHz rate and is slower,what does determine the speed of the CPU? There are a variety of factors, but we will show you the main parts of a CPU, and what they are used for.
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When looking at a CPU, there are a few basic things that we should know about it: • • • A CPU has four basic tasks that it performs. They are Fetch, Decode, Manipulateand Output. Speed rating, although not accurate, is almost always measured by MHz. The CPU speed is determined by a combination of raw MHz as well as design and other features such as the FPU of the chip.
Before we get into details about how it works, we must remember that, like many other computer parts, the CPU is comprised of millions of logic gates embedded into it which then are used tocomplete a variety of different operations. The size of the CPU core, the part with the logic gates, can be as small as the size of a smaller coin. The gates are used with a clock that regulates the speed at which the CPU is fed data. The speed at which it does this is measured in Hz (amount of clock pulses in one second), MHz (about 1 million Hz) and GHz (about 1000 MHz). If there was no clock toregulate the data flow, the CPU would be unorganized and useless. The clock does a similar thing for the CPU as traffic lights do for the traffic. It makes everything organized and tells when the data should pass through, and when it should not.
Aside from the high MHz speed, Intel's MMX technology made the Pentium a dominating CPU for the PC © Intel Corp, 2001
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As you could guess, if you read the binary part of the website, the CPU processes only binary data. This means that all of the data, such as numbers, letters, colors, or actions to be performed, are stored in bits and bytes. To process data, a CPU really only needs 6 basic parts to do its job: Instruction This tells the CPU where the instructionor data is stored. Before a Pointer CPU can process data, it needs to know where the information should be taken from. Instruction Takes the instruction and data from the part of the memory that the Fetch instruction pointer specifies. Instruction Takes the instruction from Fetch, and decodes it so that it can be Decoder used by other parts of the CPU or the Computer. Register ALU Control Unit...