CPU speed is the central factor in a computer's performance. While many people use the clock speed of a CPU to gauge performance, this is not the only variable to consider. Elements such as the front side bus and cache also play an important role in CPU speed.
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Overview of CPU Performance
The most common measure of CPU speed is the clock speed, which is measured in MHz or GHz. One GHz equals 1,000 MHz, so a speed of 2.4 GHz could also be expressed as 2,400 MHz. The higher the clock speed, the more operations the CPU can execute per second. It's important to realize that the clock speed of a CPU is not the only factor determining performance. Because of differences in chip architecture, one processor may be able to perform more operations than another over one cycle. Therefore, even if the first processor has a lower clock speed than the second, it may actually be faster.
Some processors are "dual core" or "quad core." These terms indicate the use of multiple CPUs on a single circuit. The idea behind this concept is to improve processing speed by using two or more processors that can run independently or cooperatively. The actual advantage over a single core processor varies because software usually has to be optimized for multi-core processors in order to gain a significant speed advantage.
Front Side Bus and Cache
With any processor, the cache and front side bus play an important role in speed. The CPU and front side bus work together, so they should ideally run at the same speed so that one cannot slow the other down. The cache also plays an important role in processor speed. The cache is memory that is accessed by the CPU to aid in completing certain routine tasks faster, so the larger the cache, the greater the CPU performance.