PC Hardware in a Nutshell, 3rd Edition

Processor Components

Modern processors have the following internal components:

Execution unit

The core of the CPU, the execution unit processes instructions.

Branch predictor

The branch predictor attempts to guess where the program will jump (or branch) next, allowing the prefetch and decode unit to retrieve instructions and data in advance so that they will already be available when the CPU requests them.

Floating-point unit

The floating-point unit (FPU) is a specialized logic unit optimized to perform noninteger calculations much faster than the general-purpose logic unit can perform them.

Primary cache

Also called Level 1 or L1 cache, primary cache is a small amount of very fast memory that allows the CPU to retrieve data immediately, rather than waiting for slower main memory to respond. See Chapter 5 for more information about cache memory.

Bus interfaces

Bus interfaces are the pathways that connect the processor to memory and other components. For example, modern processors connect to the chipset Northbridge via a dedicated bus called the frontside bus (FSB) or host bus.