Difference between revisions of "CPUs"
| Line 36: | Line 36: | ||
==CPU measurements== | ==CPU measurements== | ||
| − | Due to it's circuit implementation a modern CPU is very fast, at least three orders of magnitude faster than modern [[RAM|memory]]<ref>Anastassia Ailamaki: '''''A Storage Model to Bridge the Processor/Memory Speed Gap''''' Available from:[[http://www.cs.cmu.edu/~natassa/aapubs/conference/storage%20model%20to%20bridge.pdf | + | Due to it's circuit implementation a modern CPU is very fast, at least three orders of magnitude faster than modern [[RAM|memory]]<ref>Anastassia Ailamaki: '''''A Storage Model to Bridge the Processor/Memory Speed Gap''''' Available from:[[http://www.cs.cmu.edu/~natassa/aapubs/conference/storage%20model%20to%20bridge.pdf Carnegie Mellon]] Accessed: 28 November 2008</ref>. |
When shopping for a CPU the most common indicators for performance are the clock rate and the cache size. Cache size is often measured in MB(Megabytes) and clock rate in GHz(Gigahertz). Often the higher the numbers the better, though having multiple cores will yield a lower GHz rating due to the division of resources. Most importantly be sure to get a CPU that matches your motherboard's socket type. If the socket types do not match then your CPU will not fit in your system. | When shopping for a CPU the most common indicators for performance are the clock rate and the cache size. Cache size is often measured in MB(Megabytes) and clock rate in GHz(Gigahertz). Often the higher the numbers the better, though having multiple cores will yield a lower GHz rating due to the division of resources. Most importantly be sure to get a CPU that matches your motherboard's socket type. If the socket types do not match then your CPU will not fit in your system. | ||
Revision as of 16:28, 28 November 2008
IntroductionOf all the electrical components residing in your computer, the CPU is likely the most important. CPU stands for central processing unit(Processor for short) and as the name suggests, its job is to process instructions. This is the most vital role of all the hardware, as it's ability to process instructions is what makes your computer what it is. Ironically the CPU is also likely the smallest piece of hardware in your computer, with modern CPU sizes comparable in size to a soda cracker.
|
...by studentsIf you are interested in building computers from their components, You might be interested to know that the CPU is the trickiest part to replace. This is due to the thermal paste that must be applied to it's surface, and the large heat sink and fan that must be mounted above it. The first time I attempted to remove it, I asked my father for help getting the cooling mechanism off. The night ended with him gashing my motherboard with a fork many times. |
blah blah
|
Previous Page: UPDATE THIS LINK |
Next Page: UPDATE THIS LINK |
CPU design
The CPU takes commands given to it by it's users and executes them. But how is it done?
Essentially all software that runs on your computer feeds the CPU instructions. What may be a bit trickier to understand is that all program instructions boil down to a set of commands the CPU recognizes. To the CPU, these basic commands are a series of electrical signals we interpret as ones and zeroes. Furthermore these commands are all basically arithmetic operations and shifts(pushing all ones and zeroes left or right in a series).
Arithmetic Logic Unit
It is possible to conceptualize a CPU as a really fast calculator that accepts operands and arithmetic operators, spitting out results lightning fast and if necessary, storing them to memory for later use.
The mathematical operations take place in a section of the CPU that can be labeled the ALU(arithmetic logic unit). This portion of the CPU is implemented through electrical AND and OR gates.
CPU Clock
All CPUs employ a clock function that regulates the processing of all commands. Because all commands are executed using circuitry, one command cannot start until the previous is completely finished or stored. In order to maintain a smooth flow of instructions and keep temperatures normal, the clock will be set to specific frequency in the factory it is manufactured. Modifying the clock rate is possible in order to increase performance of the CPU, at the cost of heat production and sometimes system stability. Often called "overclocking", increasing a CPU's clock speed is not recommended unless you are familiar with it.
Optimization techniques
While all CPUs fulfill their roles as the mathematical brain of the computer, nothing is ever as simple as it seems. Many advanced techniques are employed inside of CPUs to increase their speed and their ability to do more instructions at once.
Pipelining, for example is one such technique that is used to concurrently execute multiple commands on one CPU, effectively multiplying it's speed.
Many modern CPUs also contain multiple cores, allowing a CPU to execute two streams of instructions at once while splitting it's resources for each in half. Since many systems today are constantly running dozens of processes, splitting the CPU like this can produce desirable effects.
CPU measurements
Due to it's circuit implementation a modern CPU is very fast, at least three orders of magnitude faster than modern memory[1].
When shopping for a CPU the most common indicators for performance are the clock rate and the cache size. Cache size is often measured in MB(Megabytes) and clock rate in GHz(Gigahertz). Often the higher the numbers the better, though having multiple cores will yield a lower GHz rating due to the division of resources. Most importantly be sure to get a CPU that matches your motherboard's socket type. If the socket types do not match then your CPU will not fit in your system.
References
- ↑ Anastassia Ailamaki: A Storage Model to Bridge the Processor/Memory Speed Gap Available from:[Carnegie Mellon] Accessed: 28 November 2008
