There are essentially two different kinds of processors available: ARM processors, named for the company that designs them, and "x86" processors, named for the instruction set they use. Small, battery-powered devices use ARM processors. Laptops, desktops and servers use x86 processors made by either Advanced Micro Devices (AMD) or Intel. To make machines run faster, manufacturers use a technique to increase output by placing more than one processor on a single chip. Each processor is called a "core," two processors create a dual-core processor and three or more create a multi-core processor.
Processors and Power
A processor, commonly known as microprocessor or CPU, is the brain of a computer. Each time a cycle of electricity passes through the processor, it fetches instructions from programs and executes them. Faster processors have more cycles than slower processors but also require more power and generate more heat. A 2.4 GHz processor executes 2.4 billion cycles per second. Power consumption is a primary consideration in the design of microprocessors because battery-powered devices don't have a lot of power to provide and because there's a general desire to reduce power consumption for environmental reasons.
When you buy an iPhone, iPod, digital camera or tablet, you don't have a choice of processor as you do when you buy a laptop or a desktop. Almost all small electronic devices with a microprocessor use ARM processors; however, not all ARM processors are the same. ARM licenses the design to manufacturers, who may modify it before they manufacturer the chips. ARM processors don't require much power to run, which makes them ideal for battery-powered devices. However, low power means low performance, and this limits their use to devices that don't need a lot of computing power.
AMD and Intel Processors
When you buy or build a laptop, desktop or server, you can generally choose a processor from either AMD or Intel. With the exception of the Intel Atom processor, used almost exclusively in netbooks, these processors require more electric power and provide correspondingly more computing power than ARM processors. Some AMD processors are faster than Intel processors and some Intel processors are faster than AMD processors. When you buy a computer, the processor is one of several features that influence your choice. When you build a computer, you must choose a motherboard that is compatible with the processor you select.
If you add another processor to a computer, you essentially have to add another motherboard, too. A compromise is to place multiple processors on a single chip. The processors share the resources that the motherboard provides, such as access to memory. To the motherboard, it appears as though there's only one processor, when in fact there may be two, four, eight or more. Each processor is called a "core" and the collection is called a dual-core or multi-core processor. ARM, AMD and Intel use this technique to increase output without increasing the number of cycles per processor.
- IEEE Spectrum: The Battle Between ARM and Intel Gets Real
- Tech Radar: Intel vs. AMD: Which Processor Is Best?
- Newegg: AMD-Compatible Motherboard Buying Guide
- Techreport.com: Mercury Research: AMD's CPU Share Grew Last Quarter
- CNET: Intel Launches E5 Xeons, a Faster Mainstay of the Server Market
- Tech Radar: Intel's Sandy Bridge E Chips are Finally Here
- AMD: Multi-Core Processing with AMD
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