1.1.2 CPU performance

Question 1

State the factors that can affect a CPU’s overall performance

Answer 1

Clock Speed
Cache Size
Number of Cores

Question 2

Define Clock speed

Answer 2

The amount of Fetch-Decode-Execute cycles a single processor core can carry out per second

Question 3

What is clock speed measured in?

Answer 3

Clock speed is measured in hertz

Question 4

What is hertz

Answer 4

number of cycles per second

Question 5

What is 3.2GHz

Answer 5

3.2 billion cycles per second

Question 6

What is the fetch-decode-execute cycle controlled by.

Answer 6

The fetch-decode-execute cycle is controlled by the control unit and the CPU’s internal clock.

Question 7

How does a higher clock speed affect CPU performance

Answer 7

A higher clock speed means a greater number of Fetch-Decode-Execute instructions are carried out per second

This means that so instructions are executed faster.

This allows for more programs to be run at the same time.

Question 8

What is cache

Answer 8

Temporary storage of data and instructions being read to and written from the RAM.

Question 9

What does cache store

Answer 9

The cache stores copies of recent data and instructions.

Question 10

How does having a larger size of Cache affect CPU performance

Answer 10

Cache stores frequently
used instructions/data that can be accessed faster than accessing them from RAM.

This means that means more cache, means more instructions and data can be stored for quick access by the CPU, which improves the performance of the CPU

Question 11

Why can too much cache be bad

Answer 11

Too much cache can be detrimental as it will take longer to find the
instructions in cache

Question 12

What does Cache provide in terms of storage instead of main memory

Answer 12

Cache means Trying to avoid going and getting instructions and data from memory (as much as possible) if we don’t need to as it costs time.

Question 13

What is a core

Answer 13

A core is a complete copy of a CPU.

Question 14

How many processors will be in a quad-core prcoessor

Answer 14

4 separate CPU’s - including Registers, ALU, control unit, etc.

Question 15

How does the number of cores affect CPU performance

Answer 15

Parallel processing can occur with a CPU that has more than one core.

Parallel processing can take place which means each processor can execute a separate instruction at the
same time. This enables multitasking

Question 16

Why isn’t it that doubling the number of cores, double the speed and efficiency of the processor

Answer 16

Some processes/software cannot be
split between two processors so it does
not increase the performance

CPU cores have to communicate with each other, this takes time.
Many programs are not designed to make maximum use out of multiple cores.

Question 17

Describe how the CPU and RAM work together to enable the tablet computer to operate

Answer 17

Programs that are currently
running are stored in the RAM

These instructions are fetched from the RAM by the
CPU where the instructions are executed

Question 18

Purpose of cache memory

Answer 18

To store instructions that is frequently used
Data does not need to be fetched from RAM