Home
About
Apple
Career
Experiences
General
Graphics
Hardware
History
Humor
Interface
Networking
OS
Opinion
Politics
Programming
Quotes
Reviews
Security
Software
Sound
Thought
Web
Cheap International
Airfare Online
Wachovia online banking
Get Free Coupons Online
Finding the perfect
discount hot tub
Payday Loans
Stock Trading Online
Stuffed Animals
Smart Investing Online
|
|
MHz or GHz
What does MHz mean?
By: David K. Every
|
Kind:
Created:
Size: |
Article
2001-09-10 03:39:41
3 KB |
|
|
 |
 any people ask questions about Megahertz (GHz.txt">MHz) or Gigahertz (GHz). Worse, some people don't ask, and assume they know what those terms mean. It isn't hard to understand - but it isn't as easy as some assume either. Many people get it wrong, and assume that MHz (or GHz) is how much work a computer can get done.
Hertz (Hz) means a cycle or a clock tick. Mega (abbreviated 'M') means million, and giga (abbreviate 'G') means billion. So a MHz is a million cycles (clocks) per second and GHz is billion clocks each second.
Each cycle is a stage or step for the computer, where it can get some instruction (or partial instruction) done. Think of an assembly line, and each clock, or each time someone rings a bell, the part being assembled moves to the next person in the line and a little more gets done, until ultimately, the completed product comes out the end of the line. So the faster you clock (ring that bell), the faster the part gets through the line.
This means that the faster the rating of the computer, or the more MHz / GHz, the faster the computer, right? Well, not completely. Each computer (processor) is designed differently. So MHz and GHz ratings only apply the same, to the same exact version of the same processor.
Imagine that you have two different assembly lines, one where at each stage there are four people working on adding things to the part, and a different assembly line where at each station they have only one person working. In theory the one with few people at each stage of the assembly line would have to have more total stages to get the entire part completed. But because there are fewer people working at each station, they are less likely to interfere with each other - so you could probably run the assembly line a little faster (go station to station a little quicker). So the stage to stage time (the MHz), could be up to two times faster, but that would probably still mean that it takes more actual time to get the completed part all the way out the other end. Or in other words, the bell is ringing faster, but that doesn't mean more actual work is getting done.
Computers (processors) work a lot like that. The more internal stages they have, the faster the assembly line can go (and the faster the clock can be), but that doesn't mean that they are always getting more work done than another processor. What also matters is how much is getting done at each stage.
Intel's processors (the Pentium3 and more so, the Pentium4) choose to have a whole lot of simple stages in their internal assembly lines. So they can clock really fast, and have high MHz and GHz ratings. AMD's Athlons processors get more done at each stage, so even when a little slower in MHz, they can be faster in getting work done. The PowerPC processor (in Macs) gets even more done at each stage, so even at half the MHz, is often faster than the Pentium4 at twice the clock rate (or more).
I also like to think of MHz like RPM's (revolutions per minute) in a car (the speed of the motor). In the same exact motor, higher RPM's would mean more power. So the same motor that can run faster, will have more power. But in two different motors it doesn't mean the same thing at all. After all, a motorcycle at 10,000 RPM's does not usually have more power than a truck motor and 5000 RPM's.
MHz is not an actual measure of performance of the computer, just how fast it is running internally.
 Format for Printing  Mail
|
|
|
|
