The CPU is the “brain” or heart of a computer and as such plays an important role in how fast and efficiently it performs. Clock speed, which measures how many instructions per second can be executed by the CPU, has a direct correlation to CPU performance which should be monitored while working, using, gaming, etc. The faster the clock speeds the more instructions that can be processed at any given time, but this also requires power so you need to find a balance between processing speed and energy efficiency.
How Clock Speed Affects CPU Performance?
CPU clock speeds are the building blocks of the CPU. They affect all other factors involved in its performance, such as cache size and power consumption. When comparing different CPUs, their clock rates should be taken into consideration for a fair comparison. For example, while one processor may run at 2GHz (2,000MHz), another may operate at 1.8GHz; this 20% difference will directly affect performance because it will take longer for the second CPU to execute instructions than the first.
The CPU speed rating is given in MHz or GHz (“megahertz” or “gigahertz”). Clock speed only measures how fast the CPU can carry out each instruction rather than how long it takes to perform an instruction. The speed rating indicates how many times per second the CPU can carry out an instruction. In this case, it is a measure of “operations per second” or “IPS.” So if a processor has a clock speed of 2.4GHz, then it means that it can perform 2,400 million operations every second.
In order to work out how quickly a computer accomplishes tasks using different CPUs you need to know both their clock rates and their performance ratings – expressed as MIPS (million instructions per second) or MFLOPS (million floating-point operations per second). For example, imagine two CPUs with the same frequency but different performance ratings: one runs at 3GHz and has a rating of 4MM FLOPS while the other runs at 1.8GHz and has a performance rating of 0.5MFLOPS. In this example, the first CPU will run twice as fast as the second one – even though they have the same clock speed, their MIPS ratings are different so therefore so is their performance.
Clock speed affects not only the speed at which data can be processed by a computer but also other factors such as power consumption and heat generation. Increasing clock speeds requires additional current to increase processing power; according to Ohm’s law, an increase in current causes a proportional increase in voltage which increases power consumption and generates more heat. Computer engineers need to find ways of coping with increased levels of heat produced by faster CPUs through methods such as improved thermal design or slowing down the clock speed.
An increase in clock speed will also lead to a reduction in battery life as more power is required from the battery. In order to balance performance and energy efficiency, there has been a trend towards improving performance by increasing processor core counts rather than increasing the frequency of each individual core.
While this does not provide a direct boost in overall performance – because an increase in cores alone does not mean that they work faster or more efficiently – it provides increased flexibility for processing resource allocation due to multiple processor “threads.” The Lenovo ThinkPad X1 laptop – Carbon is a good example of this trend: it features four cores at 1.6GHz but only two physical processors, allowing tasks to be processed through any two cores simultaneously or one after another.
When comparing two clock speed ratings, take into account the performance rating to get a fair comparison such as in this example:
- CPU 1: 2.4GHz with 4M FLOPS (MIPS) = ~800 MIPS
- CPU 2: 1.8GHz with 0.5MFLOPS (MIPS) = ~400 MIPS
In this case CPU 1 has double the speed of CPU 2 but half of its performance – it will execute instructions more quickly but less efficiently than CPU 2 because it takes twice as long for each instruction to be executed.
The combination of multiple cores and clock speeds is one of several key factors involved in processing power which must be compared when choosing a new computer or upgrading an existing one. The performance of a computer is also affected by the amount of cache memory, memory speed, and memory channel specifications; however clock speed ratings are generally used as the standard to compare different CPUs.
Although it does not give an indication of how fast or efficient a processor will be, the clock speed can be used as the basis for comparing the basic performance of one type of CPU against another so it is often quoted when comparing different processors.
1. How much faster is a CPU with a clock speed of 3GHz than one running at 2.4GHz?
The numerical difference between two clock speeds will give you an indication of how much faster the second one is but this does not always reflect the performance increase that you will see in practice. If they have similar performance ratings then you should notice a significant difference – but if their ratings are significantly different from each other then the amount of difference may be less noticeable since a processor with a high number of cores or higher cache memory can often keep pace even with a lower clock speed rating.
Speed Rating Approximate Performance Increase 2x 1 MFLOPS ~30% 3x 0.3 MFLOPS ~100% 4x 0.1 MFLOPS ~400%
2. What is a microsecond?
One second contains 1,000 milliseconds which are each one-thousandth of a second. When comparing two clock speeds it is common to list the time in both seconds and milliseconds (e.g. 2.4GHz = ~2.4×10 6 ) because the difference will be significant when dealing with thousands or millions of clock cycles per second – but it can be less noticeable when dealing with hundreds of millions or billions because there will always be an offset between them that increases as they get further apart like adding water to a bathtub: The more water that gets added, the bigger the increase in overall volume, but after a certain point the size of the increase will decrease gradually as more and more water is added.
3. What is FLOPS?
FLOPS, or Floating Point Operations Per Second, is a standard method of measuring the performance of computers and other devices since it enables them to be compared with each other fairly. The benchmark for many processors is given in MFLOPS (Millions of FLOPS) which refers to operations per second so the benchmark for one CPU might be 0.5MFLOPS while another might be 800 MFLOPS. A Giga-Flop (GHz) unit has been used on some CPUs such as those from AMD where 1 GHz = ~1000MHz but this has now been superseded by the exaflop (ESF), Peta-Flop (PHz), and Tera-Flop (Thz).