CPU Performance: Systems Architecture: Computer Science: GCSE (9:1)

Core

A single processing unit in a CPU. It contains a full set of components: CU, ALU and Registers and can execute a single instruction every clock cycle

Dual core

A CPU with two processing units. It can execute up to two instructions every fetch-execute cycle

Quad core

A CPU with four processing units. It can execute up to four instructions every time the clock ticks

Clock speed

The speed of operations in a CPU, it's the number of fetch-execute cycles performed in one second. Usually measured in GigaHertz (GHz). Speeding this up will improve performance.

Hertz

A unit of frequency, the number of times per second something happens.

Cache

If this is larger it will speed up the computer because the CPU will do fewer fetches from RAM. It is small, fast memory inside the CPU

Multitasking

An operating system feature that allows the computer to run many programs at the same time, which can take advantage of multicore CPUs

Parallel processing

Executing multiple instructions of the same program at the same time, which can make good use of multicore CPUs

GigaHertz

Clock speeds are usually measured with this large unit, it means a billion cycles per second

Multicore

General term for any CPU that contains more than one core. Each core is an independent processor with ALU, CU and Registers and can execute one instruction per clock cycle.

2 billion

Number of instructions per second executed by a single core CPU with a clock speed of 2GHz

4 billion

Number of instructions per second executed by a quad core CPU with a clock speed of 1GHz (assuming the programs are all suitable for multitasking or parallel processing and so make full use of all cores)

3 billion

Number of instructions per second executed by a dual core CPU running at 1.5GHz (assuming the programs are all suitable for multitasking or parallel processing and so make full use of all cores)

Performance

The speed a computer runs your programs, it is affected most by clock speed, number of cores and size of cache memory.