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Written on July 31, 2006 by Richard Millard
Always look at the date when you read a hardware article. Some of the content in this article is most likely out of date, as it was written on July 31, 2006. For newer information, see our more recent articles.
The processor is the part of the computer that does the math. Every single thing your computer does involves your processor running many (most likely millions) of calculations, and telling the rest of your system how to behave.
Certain applications are especially calculation heavy. Playing games, editing videos, pictures or music, and any sort of 3D design or modeling are all very demanding on your CPU, so it's important that you choose your processor wisely. In fact, when I help people configure a system, the first step is determining which CPU will work best for their applications.
There are many different types of processors being manufactured by different companies, but for the purpose of this article, I'll stick to the two companies that comprise 99% of the market share: AMD and Intel. "Which is better?" is not an easy question to answer. People have written volumes extolling the virtues of one processor, while condemning the flaws of others, and these battle lines are constantly being redrawn as contemporary hardware evolves.
Processors are reaching speed limits where they can't get any faster while remaining stable and not overheating. The newest trend to combat this challenge is by moving to Dual Core processors. Think of this as 2 processors being combined into a single physical chip. Your system can split up the load between the two of them, giving you a performance increase without pushing processors beyond the stable heat limits.
Dual Core processors are being embraced by more and more developers, and their costs have dropped to make them competitive with the rest of the market. Even programs that aren't specifically written for dual core processors can still have a performance increase when your operating system can use one core to handle a good portion of the background tasks. Multi-tasking is the true strength of Dual Core processors. With a new version of Windows around the corner that promises more system overhead, I find that I have a very hard time recommending single-core processors these days.
What do the numbers mean?
The Megahertz Myth
Each processor has a clock speed, which is the approximate number of mathematical operations that the CPU can do per second. The latest processors are breaking 3.8 Billion calculations per second. Initially, the idea seems pretty simple: The faster the clock speed, the better the processor, right?
Unfortunately, no. It's not that simple.
Processors have to move data along paths called "pipelines", and the length of these pipelines are different, depending on the CPU. AMD processors tend to have much lower clock speeds, but also shorter pipelines. Think about it this way: Intel has a longer distance to drive, but drives a faster car. The AMD CPU's have slower cars, but live very close to their destination.
So, when choosing a processor, don't be fooled by the "megahertz myth". Different processor architectures are really apples and oranges, and it's very hard to compare them. The best way to do this is by examining "Benchmarks" from a reputable source. The goal of a benchmark is to keep all the other variables in a system constant, while comparing the real-world performance differences between different hardware. One of the best websites around for this is Toms Hardware Guide. You can find their hardware CPU charts here: http://www23.tomshardware.com/cpu.html
They include a wide variety of benchmark tests, which simulate the different type of applications you might be using: Gaming, 3D Rendering, Video Editing, File Compression, etc.
Selecting the right processor can be tricky business. It's often really hard to know which applications are particularly CPU intensive, and which aren't. Here are a few guidelines to help you out.
Highly demanding tasks: Video games, any sort of encoding (music or video production), media editing (pictures, video, music).
Less demanding tasks: Internet Browsing, email, office applications, listening to music, watching videos.
If your computer usage falls under the "Highly demanding tasks", you should consider a CPU on the upper end of the market, and invest a significant portion of your computer budget here. For example, if you're doing a lot of multi-tasking, or any sort of Media Editing or Encoding, you will see significant performance increases from a "Dual Core Processor". If your tasks don't demand much of the processor, then aim for the "sweet spot" of the market, which is where you get the most bang-for-your-buck. Generally this "sweet spot" region is found in the middle of the modern processor lineup.
There's also a specific niche of processors designed to be low-power and low-temperature. These should be seriously considered if you're purchasing a laptop or a computer where fan-noise is a serious concern. Any salesperson at any respectable company should be able to help you with this decision.
Did you know that Windows has a built in CPU Usage Monitor? When running Windows XP, hit Ctrl + Alt + Delete, to bring up the Task Manager. Select the tab at the top labeled "Performance". Now go about your day with that monitor running in the corner of your window, and keep an eye on it. If you're running your favorite program, and the CPU Usage never drops below 100%, you've identified one major bottleneck -- your CPU!
These days, there's very little reason not to buy Dual Core. Even for laptops, they're starting to produce low-voltage Dual Core CPUs. If you're in the market, I recommend you seriously consider a Dual Core Processor.
I also recommend investing more in your CPU than other areas of your system, if you're on a tight budget. It's easy to add more RAM, or upgrade your Video Card down the road, but replacing your CPU is a bit trickier - You'd have to remove the Fan, insert the new CPU (don't bend any pins!), reapply thermal grease, and remount the fan. So, investing in a solid CPU can save you a lot of headache down the road, while many of the other components are a relatively painless upgrade.