Section 1 - Chapter 2: Processor Performance Flashcards
What are the factors affecting processor performance?
The main factors affecting processor performance are:
- Clock speed
- The number of cores
- The amount and type of cache memory
What is clock speed?
The system clock generates a series of signals, switching between 0 and 1 several million times per second and synchronizing CPU operations. Each CPU operations starts as the clock changes from 0 to 1 and the CPU cannot perform operations faster than the clock cycle. The greater the clock speed, the faster instructions will be executed
How do the number of cores improve processor performance?
Each core is theoretically able to produce a different instruction at the same time with its own fetch - decode - execute cycle. However, it does not always perform twice as fast, because the software may not always be able to take full advantage of both processors
What is cache and how does it improve processor performance?
Cache is a small amount of expensive, very fast memory inside the CPU. When an instruction is fetched from main memory it is copied into the cache so if it is needed again soon after, it can be fetched from cache, which is much quicker than going back to main memory. As cache fills up, unused instructions or data still being held are replaced with more recent ones.
What are the different levels of cache?
- Level 1 cache is extremely fast but small
- Level 2 cache is fairly fast and medium-sized
- Some CPUs also have level 3 cache
What is Pipelining and how does it improve processor performance?
Pipelining is a technique used by some processors to improve performance. Using Pipelining, the computer architecture allows the next instruction to be fetched at the same time as the processor is performing arithmetic or logical operations, holding them in a buffer close to the processor until the instruction can be performed.
What is instruction and arithmetic pipeline?
Processor pipelining is sometimes divided into instruction and arithmetic pipeline. The instruction pipeline consists of the stages in which an instruction is moved through a processor, include its being fetched, buffered and then executed. The arithmetic pipeline represents the parts of an arithmetic operation that can be broken down and overlapped as they are performed.
