If your Mac is slow don’t start by downloading another program that claims it can boost your Mac speed and find or clean your Mac in minutes. Many times these don’t help fix what’s at the root of the issue.
If you have not restarted your Mac in a long time, start by doing that and seeing if it helps with the speed.
The first place you need to look to fix a slow Mac is the Activity Monitor. This is a overview of everything happening on your Mac. By looking here you can see what is using your Mac’s power and memory, which will let you see what you need to limit or upgrade.
The fastest way to open this is to press Command and Spacebar at the same time and type Activity Monitor. Or you can go to Applications -> Utilities -> Activity Monitor.
We want to look at the CPU and Memory tabs. If you are running a very intensive application or if one is broken it may be using up too much CPU or hogging memory. Click on the Memory column to sort by what is using the most memory.
If you identify something that is using an obscene amount of memory compared to other applications you can close the app. The best way to do this is to go to the app that is the root of the issue and choose to quit it from the menu. If it is locked up, you can click on the name in Activity Monitor and then click the stop sign with an X through it in the upper left.
If you frequently have issues with a slow Mac, you may need to upgrade your RAM. You can do this on many older Macs and with some of the desktop Macs, but the iMac 21", MacBook Pro Retina and MacBook Air RAM upgrades aren’t possible.