With the exception of the central processing unit (CPU), most hardware within a computer has two numbers that can help to determine the speed of the system. The first number is the amount of the resource provided, such as the volume of a hard drive or the capacity of the random access memory (RAM) chips. The second number is the speed at which the hardware operates, which can cause other components inside a computer to become slower if it is too low. Software also determines computer speed, specifically how many programs — or processes — are running in the background and taking up computer power and resources. Overall computer speed ultimately is largely determined by how well all the software and hardware components operate together.
At the center of a computer is the CPU, which is the main processor that performs most of the operations within a computer or delegates tasks to other components. The faster a CPU, the faster a computer will be in most cases, although other factors can mitigate the increase in computer speed. The cache, which is a buffer between the CPU and hardware such as a hard drive, can cause the CPU to operate slowly if it is not fast enough to feed information to the CPU or accept it quickly from hardware. Additionally, the circuits known as buses on the motherboard serve as the primary pathways for reading from hardware, and they need to be as fast as the CPU. If these components are not assembled so they have complementary speeds, then the overall computer speed will be slower than expected.
The size and rate of the RAM also can affect computer speed. RAM is used to hold information in a location that can be accessed quickly, allowing programs to run fast, and large data calculations to be made efficiently. Like other components, RAM has a given speed that determines how fast information can be read and written to it. If there is an insufficient amount of RAM in a system, then the computer will start to use the hard drive as a virtual RAM disk, which is accessed at a much slower rate.
A computer’s hard drive, the physical storage device, can affect computer speed. Aside from the speed of reading and writing operations and the amount of available space, which the operating system uses to temporarily store memory pages from RAM, a hard disk can suffer from disk fragmentation. Disk fragmentation occurs when information, such as a program or a document, is not stored in consecutive memory locations but instead is spread across many areas of a hard disk. This means the drive must jump to several random physical locations to assemble a single file, slowing execution. Regularly defragmenting a hard drive can solve this problem.
The software that is installed also can reduce computer speed. When a computer initially starts, certain programs and drivers are loaded into memory. Many of these are vital for the computer’s operation, but some are not and simply occupy memory, processor cycles and, potentially, network bandwidth. Managing the amount of processes that are running at any given time, as well as other programs that might be in the background, can increase computer speed significantly and release valuable resources for other programs to use.