Microprocessor design grows more complex with each generation, and CPU packaging keeps changing to provide room for additional features and operating requirements. Microprocessors have evolved from the 4004 described earlier into today's high-speed Pentiums. Each new processor has brought higher performance and spawned new technology. Six basic elements are customarily used to gauge the performance and capability of a CPU design.
• Speed. The maximum number of clock cycles measured in MHz. The higher the speed, the quicker a command will be executed.
• Number of transistors. More switches means more computing power.
• Registers. The size (in bits) of the internal registers. The larger the registers, the more complicated the commands that can be processed in one step.
• External data bus. As data bus size increases, so does the amount and complexity of code (information) that can be transferred among all devices in the computer.
• Address bus. The size of the address bus determines the maximum amount of memory that can be addressed by the CPU.
• Internal cache. The internal cache is high-speed memory built into the processor. This is a place to store frequently used data instead of sending it to slower devices (speed is relative in computers) such as RAM and hard disk drives. It is built into the processor and has a dramatic effect on speed. We cover cache in more detail later in this lesson.
Intel has held most of the PC CPU market share since the original IBM PC was introduced. Closely following each new Intel launch, rivals such as Advanced Micro Devices (AMD) and Cyrix have offered alternative chips that are generally compatible with the Intel models. This development, in turn, drives prices down and spurs a new round of CPU design. Another player is Motorola, a firm that manufactures the microprocessors used in the Apple family of computers, among others.
No comments:
Post a Comment