Front Side Bus and why it's important when choosing your new PC

On this website, and many others that deal with selling computers, you'll often see a reference to something called 'FSB', combined with a number. Here's a typcial example from this website:

(2.20GHz, 800MHz FSB, 1MB cache)

If you're in the market for a new computer, this FSB rating is very important to you and can have a big impact on the speed of your PC. So what is the FSB and what should you be looking for?

FSB stands for Front Side Bus. The FSB is a part of a computer's motherboard that takes the form of an electrical pathway. It connects the CPU to other important components in the PC. One of the most important jobs the FSB does is moving information between the processor and the memory (the ram).

Although people generally look at the processor speed when choosing a new computer, the speed of the FSB is often overlooked. This is a mistake because a fast FSB isn't just something geeks looking to make their own computer should be concerned about - it has a huge effect on the speed of your PC.

As the FSB acts as a go-between for the CPU and other components, if it's not fast enough, you'll get a bottle neck of data waiting to get in and out of the processor. This isn't harmful to the PC but it means that the processor will be idle and won't be able to achieive it's full 'speed'.

Even if you've got the very latest CPU, it can be a complete waste of money if the FSB isn't keeping up with the work load.

The speed of FSB is measured in Megahertz and Gigahertz (the same measurement used to rate how fast a CPU is). The larger the number, the faster the FSB will be. FSB speed is always lower than CPU speed and people often work out the ratio of the CPU speed to the FSB speed. eg. 6:1. But that's not really important.

The main thing to remember is not to only look at the CPU speed when choosing your new computer. (The larger number that's always prominent in computer shops and in ads). Always find out what the FSB speed is too.

As with all speed improving perks, the faster FSB you aim for will also come at a price. Many shops don't display the FSB speed of a computer. Fortunately you can see it on pretty much every PC description on this website.