A Mac isn’t immune as a computer, just like how a PC running Windows isn’t. While Macs are not nearly as susceptible to falling prey to viruses, spam or adware like a Windows PC, they have the potential downfall of slowing down from time to time.
However, almost all slowdowns are reversible. The only times they aren’t reversible is where there is hardware failure. Even in those cases, the performance can be corrected with hardware replacements or upgrades.
When a Mac slows down, there’s a few quick things in a checklist that you can run through, to quickly diagnose the problem. First, you will need to open up Activity Monitor when your Mac is running slow. Please note that sometimes just opening Activity Monitor might slow down your Mac even more than usual. But, it is a wait that you have to get over. Because, once you get Activity Monitor open, you will be able to see what exactly is slowing down your Mac. Check for apps that are using more than 20% of your Mac’s CPU or RAM or both. No process should be using up any more than 5% of your Mac’s CPU or RAM to run routine procedures. If CPU or RAM usage is very high, it is most probably because the app is malfunctioning and not working like it is supposed to.
But, when you have Activity Monitor open, please don’t assume that an app needs to be uninstalled just because it is making your Mac slow. Sometimes, it can just be a temporary thing. For example, your Mac’s very own Spotlight can sometimes hog as much as 40% of your Mac’s CPU, when it is running important indexing tasks. Indexing is a process that will help you in the long run and you should let it run its course, instead of stopping it. If anything, try to make way for Spotlight by killing other apps. You will find more such tips on how to speed up your Mac at http://www.whyismymacsoslowallofasudden.com.