Performance of the CPU
What is cache memory? [1] - answer Cache memory is very fast memory, usually within
the processor itself.
What are some advantages of using multi-core processors? [2] - answer1) The cores
can work together on the same program - parallel processing.
2) The cores can work on different programs at the same time - multitasking.
What are some disadvantages of using multi-core processors? [2] - answer1) Not all
programs will run at twice the speed with a dual-core processor.
2) The programs may be sequential so that one task requires output from a previous
task and so the second task cannot start until the first task has finished.
Explain why cache size affects the performance of the CPU. [4] - answer Cache is high
speed memory used to store frequently used program instructions. The larger the cache
size, the less often the slower main memory needs to be accessed, speeding up data
transfer. The performance of the CPU will be improved as it does not have to wait as
long for the data to be delivered. However, if the cache becomes too large then the data
access time increases and so the cache is split into units e.g. L1, L2, L3.
Explain why increasing the number of cores in a processor does not necessarily
increase the rate at which all programs are processed. [2] - answerNot all programs are
written to take advantage of parallel processing and some processes may not be able to
start until others are finished as they require output from them.
Give one reason why cache memory is not used for RAM. [1] - answerToo expensive.
The performance of a CPU can be improved by increasing its clock speed. Explain why
performance cannot be increased indefinitely by increasing the clock speed. [2] -
answerPerformance cannot be improved indefinitely because the rate at which the
transistors process the instructions is limited. There can also be a problem with the
amount of heat generated by high clock speeds, which may cause a malfunction if it
cannot be dissipated.
Explain why sequential programs might not run quicker with multi-core processors. [2] -
answerIn sequential programs, one task requires the output of a previous task, so the
second task cannot start until the first task has finished.
Explain why cache memory is used in the CPU. [2] - answerThe cache consists of very
fast memory and it is used to store frequently used commands and data. These can be
What is cache memory? [1] - answer Cache memory is very fast memory, usually within
the processor itself.
What are some advantages of using multi-core processors? [2] - answer1) The cores
can work together on the same program - parallel processing.
2) The cores can work on different programs at the same time - multitasking.
What are some disadvantages of using multi-core processors? [2] - answer1) Not all
programs will run at twice the speed with a dual-core processor.
2) The programs may be sequential so that one task requires output from a previous
task and so the second task cannot start until the first task has finished.
Explain why cache size affects the performance of the CPU. [4] - answer Cache is high
speed memory used to store frequently used program instructions. The larger the cache
size, the less often the slower main memory needs to be accessed, speeding up data
transfer. The performance of the CPU will be improved as it does not have to wait as
long for the data to be delivered. However, if the cache becomes too large then the data
access time increases and so the cache is split into units e.g. L1, L2, L3.
Explain why increasing the number of cores in a processor does not necessarily
increase the rate at which all programs are processed. [2] - answerNot all programs are
written to take advantage of parallel processing and some processes may not be able to
start until others are finished as they require output from them.
Give one reason why cache memory is not used for RAM. [1] - answerToo expensive.
The performance of a CPU can be improved by increasing its clock speed. Explain why
performance cannot be increased indefinitely by increasing the clock speed. [2] -
answerPerformance cannot be improved indefinitely because the rate at which the
transistors process the instructions is limited. There can also be a problem with the
amount of heat generated by high clock speeds, which may cause a malfunction if it
cannot be dissipated.
Explain why sequential programs might not run quicker with multi-core processors. [2] -
answerIn sequential programs, one task requires the output of a previous task, so the
second task cannot start until the first task has finished.
Explain why cache memory is used in the CPU. [2] - answerThe cache consists of very
fast memory and it is used to store frequently used commands and data. These can be
