Clock speed is a measure of how quickly a computer completes basic computations and operations. It is measured as a frequency in hertz (Hz), and most commonly refers to the speed of the computer's Central Processing Unit (CPU). While computer developers and users can refer to this term regarding CPU performance, this has fallen out of favor as CPUs have become more complex. The easiest ways to boost clock speed in a computer include upgrading components and "overclocking" a piece of hardware.
What Clock Speeds Measure
There is a small quartz crystal inside of a CPU that vibrates at a particular oscillation or frequency. This frequency sets the "speed" of processes in the computer and is usually very high; they are typically measured in megahertz (MHz) and gigahertz (GHz). A megahertz is one-million cycles per second, while a gigahertz is one-billion cycles per second. So a computer with a clock speed of 800MHz is running 800,000,000 cycles per second, while a 2.4GHz computer is running 2,400,000,000 cycles per second.
These cycles set the speed for all processes within a computer. This ensures that all components and memory are working together at a rate that remains harmonious. Different components and processes can also run as a fraction of the primary CPU speed, which allows each element of a computer to work on its own and still function with the primary frequency of the CPU.
Clock Speeds and Computer Performance
There is some contention over the use of clock speed as a benchmark for computer performance, and many CPU manufacturers seem to be abandoning its use as the primary performance indicator. The problem comes from the fact that although clock speed works as a fairly reliable indicator of how one chip made by a company stacks up against another of their chips, it is a poor indicator of how it might compete against a different company's chipset. Many other elements can also impact computer performance, which makes CPU speed even less effective for overall computer benchmarking. The amount of Random Access Memory (RAM) a computer has, the speed of that RAM, and the type of hard drive used in a computer can all play significant roles in determining performance.
Comparing CPUs
When comparing one Intel® chip to another, for example, the clock speed is a fairly good indicator of differences between them. All other components being equal, an 800Mhz Pentium® computer performs most processor-based tasks roughly twice as quickly as a 400MHz Pentium® computer. When comparing a Pentium® chip and an AMD® chip, however, the AMD® tends to perform most tasks faster than a comparable Pentium®.
For this reason, AMD® stopped listing clock speeds as a primary method of advertising on their computers, instead associating a number with the computer to show its performance in comparison to a Pentium®. Intel® has also begun to move away from advertising speeds, mostly due to their introduction of laptop-oriented CPUs, which have much lower clock speeds to optimize portable performance. If only the speed was indicated, these processors would appear inferior to their desktop CPUs.
Improving CPU Performance
There are a number of ways in which a computer user can increase the speed of his or her computer. Upgrading an older CPU to a new one, for example, can provide hardware with a higher clock speed or multiple "cores." Multi-core processors are essentially two or more CPUs in one, which offer greater performance for software programs that can take advantage of multiple cores.
It is also possible to "overclock" a processor. This basically increases the clock speed of a CPU beyond what is recommended by the manufacturer, allowing the computer to run faster. Overclocking a CPU is not generally recommended, however, as it produces additional heat that can damage the processor or other components and typically voids most computer's warranties.