Processor Performance Flashcards
What are the 3 main factors effecting processor performance?
Clock speed, The number of cores or duplicate processors linked together on a single chip and the amount and type of cache memory
What does the system clock generate?
A series of signals, switch between 0 and 1 several million times per second synchronising CPU operations with each CPU operation starts as the clocks change from 0 to 1 and the CPU cannot perform operations faster than the clock cycle
What do all processor actives begin o?
A clock pules, although some activities may take more than one clock cycle to complete
What is clock speed measured in?
Gigahertz (GHz), about 1 billion cycles close per second, as one clock cycle per second = 1 Hertz (Hz)
What is the typical clock speed for a PC?
Between 2 and 4 GHz,
What will happen with greater clock speeds?
The faster instructions will be executed
How many processors does a dual-core processor have and a quad-core processor have?
dual-core processor = 2
quad-core processor = 4
How is a processor theoretically faster with a quad-core chip?
As each core is able to process a different instruction at the same time with its own fetch-execute cycle
Why may dual-core or quad-core processors not always be able to take full advantage?
Because the software ,a not always be able to take full advantage of all the processors
What is cache?
Cache is a small amount of expensive, very fast memory inside the CPU
When is cache used?
When an instruction is fetched from main memory it is copied into the cache so of it os needed soon after, it can be fetched from cache, which is faster than going back to main memory
What happens when cache fills up?
Unused instructions or data still being held are replaced with more recent ones
What are ‘levels’ of cache?
Level 1 cache is extremely fast but small (between 2-64KB), level 2 cache is fairly fast and medium-sized (256KB-2MB), some CPUs have level3 cache
What is pipelining?
A technique used by some processors to improve performance, the computer arithmetic allows the next instruction to be fetched at the same time as the processor is performing arithmetic or logic operations, holding them in a buffer close to the processor until the instruction can be performed
What is a word?
A group of bytes, in memory has its own specific address
