Which? uses cookies to improve our sites and by continuing you agree to our cookies policy

How to buy the best PC

By Callum Tennent

With so many PCs available to buy, how do you narrow down the options? Here’s how to find the perfect model for you.

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

What makes a great PC isn’t based entirely on technical specs, although these certainly play a part. It also comes down to what suits you best. You may want a computer with a small screen to save on space, or a model that has a solid-state drive for a quiet, quick start-up. 

Do you want to watch movies on your new PC? Or do you simply need something to check Facebook on? With so much variation in computer prices and their specifications, this guide will help you find one that suits both your personal needs and your budget. Read on to find out just what to look for when buying your new computer.

If you're tired of sitting in front of a slow desktop PC with a dull screen and weak sound, take a look at our Best Buy all-in-one PC reviews.

Buying the best PC for you

There was once a time when the term 'PC' was straightforward and simple. Nowadays, though, there are three key sub-divisions that you should be aware of before you go out to buy a new computer. There's the all-in-one, the mini-all-in-one and the desktop (also known as 'tower'). This guide will help you decide which is best for your needs, and what to expect from each.

All-in-one PCs

This is the most common PC we review, often written simply as 'AIO'. The workings of the PC itself live inside the slim monitor. AIOs are great for saving space (and money). Fewer cables means they're nice and tidy, need only one plug socket and require very little set-up. There's also a huge range of them, from the most impressive and expensive Apple iMac to the most bare-bones, budget Windows machine.

The price of the cheapest all-in-one we've recently reviewed.


  • Compact
  • Versatile
  • Healthy market with lots of reviewed models


  • Less individual choice over certain specs
  • Can be quite heavy to move

Mini all-in-one

The term 'mini all-in-one' is actually slightly misleading. You may also see it referred to as a 'miniature desktop', as that is essentially what it is. While all-in-ones have a screen built into their main body, mini all-in-ones do not. Instead, their emphasis is on packing a capable, fully featured PC into as small a body as possible. Even Apple does it, with the popular Mac Mini.

Usually cheaper and, of course, smaller than their AIO big brothers, they're not without their flaws. For one, you'll need to buy a monitor, keyboard and mouse separately to accompany your new mini all-in-one, which can often end up raising the price over that of a regular AIO. They also often have fewer ports because of their small frame, and never feature a DVD drive for the same reason.

103mm x 102mm x 150mmThe smallest mini all-in-one we've ever tested


  • Space-saving
  • Cheap
  • Portable


  • No screen or peripherals
  • Fewer ports
  • No DVD drive

Desktop/tower PC

The desktop PC may be old-fashioned, but it's still popular. These days, most of the desktop PC market is comprised of either high-spending, technically knowledgeable power users, or businesses buying them en-masse to equip whole offices.

But there's little reason for you to buy one instead of an AIO or a mini all-in-one, which take up less space and can be good value. Desktops are bigger and more expensive than mini all-in-ones while offering little extra functionality, and, unlike AIOs, you need to buy a separate monitor. In fact, you're probably on this page right now as you're looking to replace your desktop. We no longer review individual desktops, but we do report on the reliability of desktop brands, in case you decide to seek one out. 

10%The year-on-year decline in conventional desktop PC sales worldwide.


  • Cheap to buy second-hand
  • Lots of ports and a DVD drive
  • Huge amount of choice


  • Dated
  • Niche
  • No standout qualities

PC storage space

Storage capacity, measured in gigabytes (GB) or terabytes (TB, equal to 1,000GB) determines how much data your PC can hold. Documents, photos, music, movies, programs – they all take up space on your hard drive. Bigger is usually better, although solid-state drives (SSDs) are usually more expensive than conventional hard drives, and offer considerably less space – on the other hand, they load more quickly and are completely silent.

PC processors

The processor is the brain of your computer. Generally, the more gigahertz (GHz) a PC has, the faster it will be. Picking a processor is like walking through a minefield of specifications - you can find dual, quad, hexa or octa-core processors. The more cores your processor has, the better it will be at running multiple programmes at the same time. The processor is one component that can really ramp up the price of a computer.

All-in-one displays and choosing a monitor

The screen is a very important part of your experience when using a computer, and it's the key difference between an AIO and a mini all-in-one or a desktop. When buying an AIO the screen is effectively set for you, but when buying either of the other two you'll need to go out and buy a screen separately.

Generally, you'll want one with a resolution of 1,920x1,080 pixels (Full HD), as more pixels make for a sharper image. That said, on a smaller display (say, 19 inches or so) you may not notice too much of a difference at lower resolutions.

PC memory (Ram)

Not to be confused with storage, memory is measured in ‘Ram’ and determines how much information your computer can store in its short-term memory (whilst hard drive storage represents its long-term memory). More Ram means quicker load times and smoother switching between programmes. 4GB is the standard nowadays, with anything more being a bonus.

PC ports and drives

One factor to consider when deciding between an AIO, desktop or mini all-in-one is that the latter will not come with a DVD drive (sometimes an AIO won't, either). When it comes to ports, the more the merrier is the general rule. Bear in mind that you'll need at least two for a keyboard and mouse. USB 3.0 is considerably faster than USB 2.0, too, so look out for those wherever possible.

Now that you know what to look out for you can find the perfect all-in-one for you on our desktop PC review homepage. If you still can't find what you're looking for then you may also want to take a look at our laptop reviews, too.


Related products

See all all-in-one pcs