CPU Performance And Processor Type Flashcards
What are the 4 key factors that affect CPU performance?
- Cores
- Clock speed
- Cache size
- Processor type
Will doubling the number of a computers core double its speed?
No, CPU cores have to communicate with each other through channels which take up some of the extra speed so the more cores there are the more speed is taken by channels
What is clock speed?
Clock speed, also known as clock rate, indicates how fast a CPU can run
What is clock speed measured in?
Clock speed is measured in megahertz (MHz) or gigahertz (gHz)
How many instruction cycles can a 2 gHz CPU perform in a second
2 billion
Where do you change the maximum clock speed of a computer
In the computer BIOS
What is it called if you increase a CPU clock speed to try and make your computer run faster?
Overclocking
Why is overclocking dangerous if done wrong?
There are limits to how fast a computer can run so it’s circuitry cannot always keep up with an overclocked speed.
If the clock tells the CPU to execute instructions too quickly, the processing won’t be completed before the next instruction is carried out.
If the CPU can’t keep up with the pace of the clock, the data is corrupted.
CPUs can also overheat if they are forced to work faster than they were designed to work.
What is cache and what is it used for
Cache is a small amount of memory which is part of the CPU, closer to the CPU than RAM. It is used to temporarily hold instructions and data that the CPU is likely to resuse
Why does the control unit check cache for instructions before requesting data from RAM?
It saves fetching instructions and data repeatedly from the RAM, a relatively slow process which otherwise might keep the CPU waiting. Transfers to and from cache take less time than transfers to and from RAM.
What are the different grades of cache?
L1 - usually part of the CPU chip itself and is both the smallest and the fastest to access.
L2 and L3 - Bigger than L1. They are extra caches built between the cpu and the RAM
What are the two processor types
CISC (complex instruction set computing) and RISC (reduced instruction set computing)
