Desktop memory is the fast, efficient information buffer which holds all the data your CPU needs to get hold of quickly. Increasing its size, or overclocking its speed, can reap huge benefits to overall system performance.

1 Deciding what you want

How much memory do I need?

*Windows XP requires a minimum 128MB RAM to run, but for most people, optimal system performance is about 1GB.

* Windows Vista requires a minimum of 512MB RAM, but 2GB is really the amount that you should have, and for best performance 3-4GB is advised.

* 32-bit versions of Windows can’t see 4GB of RAM, so anything over 3GB is wasted.

That’s a lot of extra memory, what’s it for?

*If Windows services are being read off the hard drive because there’s not enough room in the RAM, they’ll be slower and so will your machine.

* Every running application will require more memory. Some, such as photo editing apps or games, need lots. Others, such as web browsers and email clients, don’t.

How much faster will my PC be if I upgrade?

* If you’re running Vista with less than 2GB of RAM, you’ll see a big leap in desktop performance after you upgrade.

* Games, and especially online games such as //Age Of Conan//, need a lot of RAM.

What sort of memory do I need?

*Check your motherboard specs for memory compatible with your system.

* Desktop memory mostly comes in either DDR2 or DDR3 types. If your system is older, it may need ordinary DDR memory.

* DDR means Double Data Rate – the RAM can transfer data on the rising and falling ticks of a clock cycle.

* The speed of the RAM is usually written after the type, DDR2 800MHz for example.

* RAM speed is also written as bandwidth. For example, DDR2 800MHz is also known as DDR2-6400, because it has a maximum transfer rate of 6.4GB/s.

* Older systems may still use DDR

What speed of memory do I need?

* It’s a good idea to go for the fastest that your motherboard supports. In most cases DDR2 800MHz will be the best option.

* DDR2 is not compatible with DDR3 motherboards, and vice versa. DDR3 runs much faster, but has a higher latency and is prohibitively expensive at the moment.

* The common speeds of memory are 667, 800 and 1066MHz, while enthusiast chips that will run at 2000MHz can be found.

What other specifications should I watch out for?

* Other memory timings are listed as a series of numbers, such as 3-4-4-8.

* The first number – the CAS latency – is the most important. The lower this is, the faster the memory will be.

CAS? What’s that?

* Column Access Strobe – it’s basically part of a measure of the number of clock cycles between the computer asking for data from the memory, and the memory delivering it.

* It’s also sometimes written as CL.

* There are other timings, but generally the CAS latency will give you the best indicator of a chip’s overall performance potential.

Can I overclock memory?

* Yes, and quite easily. Most manufacturers offer performance memory that’s tested for stability when run at high clock speeds – for a premium price, of course.

* Overclocking, overheating or mishandling memory sticks can damage some of the sensitive components. Memory faults are hard to diagnose and impossible to repair.

2. Seeing what’s available.

Memory standards are set by a consortium known as JEDEC (www.jedec.org), and because all PCs adhere to them, so long as the basics of your new RAM are compatible with your existing machine, it will work.

For most people, ‘value’ RAM will be perfectly fine for all their needs, but those who use memory-intensive applications – such as games or video encoding – will notice the benefits of moving to higher performance RAM.