How Important Are Computer Clock Speeds?

PC clock speeds are a bunch of baloney — at least as a method of determining which computer to buy. In this case, faster does not always mean better.

Every computer processor includes an oscillator that operates at a certain number of pulses per second. These pulses set the tempo for the processor; in most cases, a processor executes one or more instructions per clock cycle. Clock speeds are usually measured in millions of cycles per second (megahertz) or billions of cycles per second (gigahertz).

Average processor clock speeds have gone up quite a bit over the past 10 years. As recently as 1990, a high-performance IBM 8088 processor ran at less than 5MHz. Today, processors from Intel and other vendors routinely run well over 3GHz.

Clock speeds aren't a good measure of computing power because there are simply too many other variables. The design of the processor, the computer's system architecture, the system software, and even the amount of memory in a computer all make a huge difference. By the time you take into account all of the other factors that can affect a computer's performance, the clock speed doesn't have nearly as much impact. In fact, I can imagine a lot of situations in which a system with a 200MHz processor would beat the socks off a system with a 600MHz or 700MHz processor.

PC vendors make a big deal about clock speeds because it’s an easy way to claim they have the "best" products. For some reason, the computer press routinely accepts these claims, trumpeting each of the latest advances in clock speed. These claims might help sell more computers, but they don't help consumers make better decisions about what to buy. When you're shopping for a new computer, look at the big picture, and take all of this talk about clock speeds with a big grain of salt.