PC monitors: Buying a new PC Desktop computer processors, storage and memory
The processor, or central processing unit (CPU), is the brain of the computer. The more powerful the processor is, the faster your PC will run. The speed of a processor – that is the number of instructions per second that it can carry out - is measured in gigahertz (GHz).
Also consider the number of cores. A multi-core processor effectively has more than one CPU on a single silicon chip, so it’s better able to handle multiple tasks at once. Most modern desktops have multi-core processors.
When buying a new PC, for a basic machine you’ll need a dual-core processor that runs at about 2.5GHz - this will handle everyday basic computing tasks.
A home user after a mid-range PC might consider something like an i5 quadcore processor. This is the name of a range of processors from chip-maker Intel – the more expensive processors will give better performance.
Keen gamers who want all the power they can get may be tempted by the latest high-power CPUs such as the i7, Intel’s top-of-the-range processor. However, the fastest processors don’t come cheap and will push up the total cost of a PC considerably.
Most modern desktop processors will be 64-bit – this means that they can work with chunks of data made up of 64 binary digits. Older processors were 32-bit.
PC memory (Ram)
Random access memory (Ram) is your desktop computer’s short-term memory (the hard drive is used for long-term storage). Ram stores information when you’re using the computer - the amount determines the number of different tasks a PC carry out simultaneously.
Aim for as much Ram as you can afford. All modern desktop PCs will ship with at least 1GB of Ram, but aim for 2GB or more. Older versions of Windows weren’t able to handle large amounts of Ram, but this is no longer a problem with the latest 64-bit version of Windows 7 (assuming you have a 64-bit processor).
It’s possible to add more Ram to your computer. If you’re happy opening up your PC’s case and tinkering with it, this is one of the more straightforward and cheap ways of upgrading performance.
Computer hard disk drive
The computer’s hard disk drive provides long-term storage for your data – anything you save here will still be available even if you switch off the PC. Until recently, hard drives were measured in gigabytes (GB), but now it’s not unusual to see terabyte (TB) hard drives (1TB is 1,024GB) when buying a new PC.
If you’re storing a lot of photos, videos and music, you can quickly eat into your free hard drive space, and the same is true if you install lots of big programs. However, large capacity drives aren’t too expensive.
If you need more hard drive storage at a later date you can easily add an external hard drive. See our review to find out the best one for you.
PC optical drives
Desktop PCs will usually come with a CD/DVD drive of some sort. The most common drives let you read and write both CDs and DVDs, so you can back up your data to either of these discs.
DVDs hold lots more data than CDs, and are ideal for backing up big files.
However, when choosing the best desktop PC, you might want to consider one with a drive that can read Blu-ray discs. These discs can store a lot of data, including high-definition films.
Blu-ray writers are also now available, and useful if you want to create your own Blu-ray movies from your high-definition video footage - but they’re expensive at the moment.
Computer package on a limited budget
If you’re buying a new PC on a limited budget, you’ll be able to boost the performance by increasing it to 2GB or more (basic PCs often have only 1GB), without spending too much.
A faster processor could also help the whole computer run more quickly – but the latest and fastest processors are often disproportionately pricey for the speed bonus that they offer.
How to follow the latest Which? Tech news
Are you a Twitter user? Follow WhichTech on Twitter for regular tech tweets.
Prefer RSS? Don't miss a thing with the Which? tech RSS feed.
For just the main headlines in newsletter form, sign-up to our weekly Which? tech email.
Apple iPad 2 3G data plans compared - find the best 3G plan for your iPad
Best Android tablets round-up - we look at the best iPad alternatives around
Best cheap laptops for under £500 - find the best laptop deals