Why your computer is slow and how to speed it up

A computer is generally deemed slow when things take ages to load. Click an icon to launch an app and the computer groans trying to open it. Quit the app and it churns away closing it off. Even scrolling through web pages in your browser feels like being stuck in maple syrup and trying to wade out before you drown a sweet gooey death.

These slowness symptoms probably aren’t caused by your computer being old. It wasn’t this slow when you got it, was it? So would upgrading to a new one even help? Maybe not. Let me explain what the main bits of a computer does and why you should pick a computer appropriate to the sort of stuff you’re trying to do, so you’re not throwing money at a problem you won’t solve.

Very simply (very very simply, okay), three things impact your computer’s performance:
The speed of the CPU (aka, that Intel Core i5 thingy which is a gigahertz or two)
The amount of memory (4GB, 2GB, 8GB – DDR3 RAM, not the storage capacity of the hard disk!!)
The speed of the storage (e.g: a 500GB 7200rpm hard drive)

The CPU, the RAM and the storage work together to get things done on your computer. The hard drive (storage) is where things like files and apps are kept. When you want to do something, the computer loads it up from the storage, into the memory, which is like storage, but super fast so the CPU isn’t waiting for it directly from storage. The CPU then takes things out of memory and does stuff to it, then puts it back in memory, where it can then be put onto the storage for later.

Certain tasks are more depenent on the speed of the CPU, or the storage, or the amount of RAM. Getting a faster CPU or more RAM for your computer will not always speed it up in the way you’d expect. There are people who have entire jobs, revolving around selecting the amount and type of CPU, RAM and storage required in computers, so to distill it into one brief article is impossible. But for general users, the best way to understand what speeds up what, is to relate it to common tasks:

Things improved by a faster CPU: encoding video – using Handbrake to rip a DVD, or exporting video from iMovie to YouTube. The faster the CPU is, the faster it can crunch that data. The vast majority of the time, the CPU is under utilised as, well, they’re so fast these days, there’s not much to put a strain on it except specific tasks like video encoding.

Things improved by more RAM: having multiple apps open at once – if you’ve got lots of RAM, opening Safari, Photoshop and Office all at once isn’t an issue. But if you’ve only got a small amount of RAM, once you open too many things, the computer will start to use storage, instead of memory, as a temporary stop gap. Withotu this feature, the computer will just crap out and crash as there’s not enough RAM (which is what used to happen back in the olden days of personal computing). When the computer uses storage instead of RAM, things get sloowwwww, really slow.

Things improved by faster storage: pretty much everything – loading programs, quitting programs, accessing data within applications, booting up the computer, copying files around the computer, switching between open programs. When things are loading or programs are open, the hard drive is accessed over and over, looking for the stuff it needs to load in order to do that thing you just asked it to. Faster storage speeds up this weakest link in the CPU-RAM-Storage chain.

When you have a slow computer, chances are it’s not that you haven’t got a fast enough CPU. It might be because you haven’t got enough RAM in the computer, but that’s only a problem if you’ve got too many things open. If it’s still slow after closing everything off except the essentials, then your problem is slow storage.

Even the lowest end CPUs are pretty fast these days, so unless you explicitly need to do something CPU limited (like encoding video), don’t waste your money upgrading to a faster CPU. Spend it on more RAM or an SSD instead. I won’t go into what an SSD is at the moment (that’s a whole other article), but rest assured, it’s expotentially faster than a conventional hard drive.

If you’re in the market for a new computer, don’t spend extra to get a faster CPU, spend that money instead to get more RAM, or an SSD. You will see tangible speed improvements, but you may not with just a faster CPU and a slow hard drive.