Image: Alex Cranz/Gizmodo
Computer specs can be a baffling mix of acronyms and numbers at the best of times, but it's worth learning something about them: It will help you choose a new computer, troubleshoot your old computer, and generally understand more about the relationship between the specs on the page and the experience you're getting.
Such is the complexity of the modern-day computer, we could've written an article twice this size on any one of the categories listed below (look at any graphics card forum for proof) -- but the main aim here is to help you understand the specs you see listed with desktops and laptops, and give you an idea of the difference they make to performance.
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The Central Processing Unit, or CPU, or processor, is the brains of the operation: it handles all those calculations that keep your computer actually working. The CPU inside your machine is the main (but not the only) contributor to its overall speed and performance.
CPUs have a certain number of cores, mini computing units that are effectively CPUs in their own right -- they let your computer work on multiple tasks at the same time, so the more cores the better. On top of this, each core has a clock speed, a measurement of how fast it can do its number crunching, usually measured in gigahertz (GHz).
Comparing the performance of CPUs based on core number and clock speeds is notoriously difficult (sorry shoppers). That's because multiple factors are involved, most related to the microarchitecture of the CPUs. The microarchitecture is basically the way that the cores and the other bits of a CPU are packed together.
The two big computer CPU makers, Intel and AMD, have their own microarchitecture designs. When you see references to Intel Skylake, Intel Kaby Lake, or AMD Zen (on Ryzen chips), this is what's being referred to, and newer is always better as successive microarchitectures allow the CPU to work faster and more efficiently (and use less power).
Intel and AMD also apply their own labels -- i3, i5, and i7 in Intel's case -- to indicate relative performance within a microarchitecture family. It's a useful shorthand reference to the power you can expect, with i7 CPUs the best of the bunch from Intel. In AMD's case, you're talking about Ryzen 3, Ryzen 5 and the top-end Ryzen 7.
If you want the very best processors around, you should also look out for what Intel calls hyper-threading and what AMD calls simultaneous multi-threading. These technologies effectively double the number of cores (virtually, not physically) so you've got significantly improved performance for demanding applications like video editing or CAD software.
Unless you're building your own PC from scratch, that's probably all you need to know when looking at system listings, but CPUs have numerous other specs, including the amount of high-speed memory cache and the extra graphics processing capabilities that are on board. If your CPU has enough integrated graphics oomph, you don't need a separate card or chipset, of which more below.
Image: Alex Cranz/Gizmodo
The other big factor in computer performance, particularly if you're gaming or working with a lot of video and images, is graphics.
We only gave it a brief mention in the processor section, but many Intel CPUs now come with a decent amount of graphics processing power built in, enough for most users to get by with a bit of web browsing, Twittering, essay writing and even light image editing and gaming. You can also get integrated graphics chipsets built into the motherboard as well as the CPU.
Integrated graphics share memory with the CPU and aren't as powerful as having a dedicated (or discrete) card, but it's a cheaper option that also draws less power, which is why it's often deployed on laptops where battery life is important.
Wherever it's installed on your system, the GPU (Graphics Processing Unit) churns through calculations just like the CPU does, but only the number-crunching related to rendering pictures, animations, and videos on screen. GPUs are much better at performing many operations in parallel, as you can see here, which is why they're now being used in other areas like science and encryption.
In terms of specs, it's not particularly easy to weigh one graphics card or GPU against another. You'll see reference to number of compute units (like cores in a CPU) and raw clock speed. As with a CPU, these are two key factors to consider, but also keep an eye out for FLOPS, or Floating Point Operations Per Second -- a type of maths operation particularly important in graphics.
Video card GPUs come with their own RAM or video RAM (vRAM). This works in a similar way to the computer's main RAM, but deals solely with graphics (with the same specs references to speed and bandwidth). The more RAM your graphics card has, the more pixels it can render in memory at once, which leads to games running at higher resolutions with faster frame rates.
Essentially video cards are like separate miniature computers, with processors, RAM and architecture all of their own, and the same performance factors apply.
For the non-expert, there are a couple of useful shortcuts to working out how powerful a graphics setup is without having to pour over the specs in too much detail: how much it costs and the benchmarks reported on the web.
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Random Access Memory or RAM gives your computer room to think, and the more of it the better, as long as you can afford it. When you've got 3,000 browser tabs open, the RAM is the first to suffer, because your computer's trying to remember what's in all of those 3,000 tabs at once.
More RAM helps your computer deal with bigger images and files, or more images and files at once, or more open tabs, or more applications running simultaneously -- it's not a direct measure of the raw speed of your machine but it certainly helps performance, especially when you're trying to do a lot.
If the RAM gets overloaded, your computer sometimes stores data it needs on the (slower) hard drive instead, which is one reason more RAM equals a speedier experience.
For the majority of users shopping for a desktop or laptop, all that really matters is how much RAM is installed, but dig deeper and there are plenty of additional specs to consider -- especially if you're trying to build the fastest computer you can.
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Clock speeds appear again, usually in terms of a frequency rate, which help to determine how fast the RAM can read and write data as well as how much data the RAM can handle at once (its overall transfer rate). Latency, or how fast the RAM responds to instructions, is an important specification as well.
One other prominent specification is DDR or Double Data Rate, with DDR4 being the best yet for consumer computers (and an upgrade over DDR3) -- it has faster clock speeds, lower power draw, and lower latency.
Yet more RAM specifications relate to stability and how well your RAM sticks can handle errors, but again, this isn't something that most of us will have to worry about: the performance differences only become apparent in very specialist tasks.
Other computer specs
Image: Marlon J. Manrique/Flickr
The CPU, RAM, and graphics are the main specs to consider when assessing your own computer or looking out for a new one, but there are of course other components to bear in mind as well, which you'll see in system listings.
The hard drive is very simply the amount of room you've got to store stuff permanently (it remembers its data, unlike the RAM). Need more storage? Get a bigger hard drive. Solid-state drives used in Apple's MacBooks and most high-end laptops have no moving parts and are faster than the older mechanical hard disk drives, but they're also more expensive and don't offer as much capacity. Newer technologies like hybrid drives and Intel's Optane technology are looking to find a better compromise between the two.
You probably won't give any thought to your motherboard unless you have to build a PC yourself, but it acts as the nervous system for the whole machine and connects all the various bits together. Motherboard specs, such as they are, don't make a huge difference to overall performance but they can help the key components work together more efficiently and faster. The motherboard also dictates how many input and output ports you've got on your system.
Other specs you see should be self-explanatory, like the size of your monitor or the number of memory card slots you're getting. And if you're in the market for a new phone, a lot of the specs -- processor, RAM, storage -- do the same job on these miniature computers as they do on the full-sized versions.