I Thought Hertz Rented Cars!
SHA Newsletter: Vol 1. No. 15

A few weeks ago, I sent you a newsletter on Why is My Computer So Slow? I reminisced about the good old days, when a fast computer ran at a screaming 10 MHz. My beloved one here at home, upon reading that newsletter, wondered aloud just what a “Hertz” is.

It’s a good question. Let’s answer it.

The computer is made up of a mess of circuits for moving information around, making comparisons, and doing arithmetic. The various components have to be precisely synchronized. That’s done with a master clock signal on the mainboard of your computer.

The clock acts like a musician’s metronome. The clicks of the metronome help to keep the players “on tempo”. Inside the computer, the clock sends out electrical pulses that make sure that all the circuits work at the same speed.

The clock source is sometimes a quartz crystal (which is made to vibrate at a precise rate) or an electronic module called an oscillator circuit. The clock source sends out a steady stream of on/off pulses that sets the pace for the entire machine.

The “Megahertz” or “Gigahertz” number for your computer represents the number of pulses that the computer’s clock sends out every second. Engineers call that number the clock frequency. The engineering unit for frequency is the Hertz (Hz, for short). The rest of it is a prefix for common multiples:

Kilo = 1 thousand (abbreviated K)
Mega = 1 million (abbreviated M)
Giga = 1 billion (abbreviated G)

 

So 1,000 cycles per second equals 1 Kilohertz (1 KHz). 1,000,000 cycles per second equals 1 Megahertz (1 MHz). 1 billion cycles per second equals 1 Gigahertz (1 GHz).

Why is the Clock Frequency Important?

Anything you do on a computer requires some kind of program. A computer program is a series of instructions that the computer knows how to perform, step by step. In most cases, a computer can perform one instruction per clock cycle. So the faster the clock, the faster your programs go.

The clock frequency, therefore, is a basic indicator of how fast your computer will perform. The higher the number, the faster the computer will run, all other things being equal. You can also consider the clock frequency to be a measure of how fast the computer’s central processor (CPU) chip runs.

Is That All I Need to Know?

I wish things were that simple, but they aren’t. There are many factors that influence how fast a computer will run.

Some CPU chips handle data more efficiently than others. Although they might run at a slower frequency, they might get work done faster.

Although the clock frequency is important, the practical speed of the computer also depends on the speed of memory boards, disk drives, and other devices.

If your computer uses a “soft modem” or other software-based features, they will influence the performance of your computer. While your computer might perform a billion instructions every second, a fair number of those instructions will be used up running your modem, integrated video, or network devices.

Many computers, particularly laptops, can slow the CPU chip down from its advertised clock frequency. This is done to save battery power or to help keep the computer from overheating. A computer advertised with a high clock speed might not run at that speed under all conditions.

But Why Do They Call Cycles “Hertz”?

The unit of frequency is named for Heinrich Hertz (1847-1894), the first person to broadcast and receive radio waves. Frequency is a basic measurement in radio engineering, and computer clocks use the same unit of measurement.

Please note: Any trademarks and trade names of others mentioned in this message are the property of their owners, and not Stoney Hill Associates, LLC. We respect the intellectual property of others. The information provided is believed to be reliable, but we cannot guarantee that the procedures and information given here will work correctly for your specific situation.

If you would like help with a computer or software problem you face, contact us. Send an email to request@stoneyhillassociates.com.

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