what are the factors the affect the processor performance?
- cache (position of cache, design of cache and cache memory)
- multiple cores / multicore processors
- clock speed
- word length and word size
- data bus width
- address bus width
what is cache?
a small amount of very high speed memory that sits close to or directly on the processor
what is cache used for?
used to store the instructions and data most likely to be used during processing
why does cache improve the processor performance
it is quicker to retrieve instructions from cache than main memory every time they are needed
what is the design of cache
designed for speed of access
size of cache is relatively small (direct trade off between size and access speed)
SRAM is used for cache
what does SRAM stand for
static random access memory
(higher performance technologies)
why does the position of cache matter?
having it as part of the circuitry of each core reduces the time it takes for instructions and data to pass through the system registers
what does the closer position of cache increase?
increases speed of processing and allows instructions to be carried out more efficiently
if there is a greater number of cache levels, what happens to the performance time
the faster the system can perform
what does having more cores mean?
the more cores a CPU has, the more instructions it can execute at the same time
what does a dual-core processor have?
2 processing units
what’s the name of a processor that has 4 processing units
quad-core
what’s the name of a processor that has 6 processing units
hexa-core
what’s the name of a processor that has 8 processing units
octa-core
does doubling cores, double the speed
no
what does having multiple cores mean?
they can run some instructions from a program at the same time
why does doubling cores not double the speed?
cores have to communicate with each other and have to take their turn when accessing shared resources (cache and main memory)
what is the clock?
an electronic oscillator that produces a signal to synchronise the operation of the processor
the greater the clock speed…
the faster the instructions are carried out
what is clock speed measured in
gigahertz GHz
why is clock speed a theoretical maximum?
- it’s unlikely the system will perform to the greatest stated number
- making a processor perform to more instructions per second than is recommended (overclocking) could cause the processor to overheat
what is overclocking
making a processor perform to more instructions per second than is recommended
what is the word length
the amount of data that can be handled at one time by the processor
what does the word length determine?
the size of the bit pattern that can be transferred to or from main memory in one operation
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fetch, decode, execute9
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structure of the processor38
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infix and postfix19
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computer architecture57
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types of numbers32
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factors affecting processor performance37
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boolean laws and algebra identities20
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processor interrupts14
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subroutines, structures and built-in functions18
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logic gates25
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storing objects, stack and heap27
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memory allocation19
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network protocols58
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function stubs and passing parameters6
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computer networks31
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packet switching18
