Mouse Mat home page

Hobbies

Building your own computer

Memory

184 pin DDR memoryThere are 3 main sorts of memory available today: SDRAM (rapidly going out of favour), DDR (faster and the most common form) and RAMBUS (exclusively for Intel based processors. Very fast but currently significantly more expensive). DDR is available in two main speeds: 266Mhz and the newer 400Mhz. The motherboard may well support different speeds and even types of memory. DDR is the best choice today, although that will undoubtedly change over time. Each type of memory is a slightly different size so you can't swap in the wrong memory into the motherboard.

The amount of memory in even bargain-basement computers has rocketed too. This is partly due to the increasing demands of the operating system, such as Windows XP, which cannot run realistically in less than 128Mb (megabytes), and partly because the program you run are becoming more powerful so need more memory too.

You should really think of at least 256Mb of memory, of whatever type it is that you buy. Less than this may let Windows run, but everything else will have to share it so will run very slowly. More than this may mean money better spent on other components of your system. Unless you have demanding programs (and word processing is not very demanding) that require huge amounts of memory stick to 256Mb. Of course, if you intend to capture all your holiday videos onto your PC, edit them, add a few titles and then burn the resulting movie onto DVD you probably want as much memory as you can afford, certainly 512Mb, better with 756Mb or even 1Gb (= 1000Mb).

Let's say we have decided on 256Mb as a sensible amount. Do you buy one "stick" (aka module) of 256Mb or two sticks of 128Mb each? Why would you consider the latter. Well, of all the components I have had fail on me, memory is top of the list. If that fails you will not be able to start your computer, it will just beep at you. So, by the law of averages, if you are unlucky enough to have one stick fail on you, then at least you have another one to limp by on until you can get a replacement.

On the subject of reliability, there are two sorts of memory: "branded" and "unbranded". Branded memory means a memory module which has the manufacturers name stuck on it. A tested module, backed by a big and powerful company. "Unbranded" means memory that those companies chose to reject because it did not meet their stringent testing quality. That's not to say the memory is faulty, just didn't meet the companies standards. These other memory is offloaded to whoever wants it and it is sold as "unbranded" because the manufacturers refuse to put their name to it. It's still guaranteed by the reseller of course, but the failure rate has got to be higher simply because it is memory that has failed the top quality (and top prices) of the manufacturer.

Branded memory is more expensive because it is tested more fully. Every module, not just 1 in 10. And as previously explained, some memory is rejected. But for the few pounds this might cost you (and there is not a huge difference) I most definitely recommend branded memory. Go to the www.crucial.com site for a complete run down of how they make and test their memory and you'll get the idea.

Technical note: When handling memory, do so as little as possible and make sure you are grounded to earth, or keep one hand on an earthed case. Avoid touching the pins on memory chips, as they are very static sensitive and can easily be rendered useless if you zap them with the static electricity stored in your body (generated as you walk around over carpets for example).

Final recommendation: Buy one stick of 256Mb branded memory, DDR or whatever type of memory your motherboard supports. Buying from a reputable manufacturer saves money both in the short term and in the long term!

Back to Components Page