No matter whether your Apple computer slows down at the startup or during the working process, it is not okay. You don’t expect Mac to get very sluggish, but if it happens, the best explanation is the filled up hard drive, and iMac is not an exception here. Fortunately, it is possible to breathe a new life into your computer – just find out the basic causes of the drop in system’s performance as well as several effective solutions to deal with the issue.

So, why does iMac may become a snail all of a sudden?

The Main Reasons for iMac Slow Performance

To fix the problems with iMac’s performance and make it super fast again, a user should first get acquainted with the causes of the issue. Then, it will be possible to get rid of the effects and really improve the overall device’s performance.

  • Spotlight Search. Spotlight is a built-in utility, which serves as the native iMac’s search There is no need to open Google or Yahoo each time you have a question – let the Spotlight tool do the job! However, once its index is rebuilt, the work of the system may get worse.

Find out whether Spotlight search indexing is the core problem. Go to the utility’s menu in the upper-right corner. Pull down the menu to discover an indexing bar and check whether it is running. Another alternative is to launch Activity Monitor and pay attention whether any “mds” or “mdworker” processes are on.

  • Software update. No matter whether iMac is new and updates via the App Store, or outdated and applies Software Update – such processes often lead to a temporary drop in the computer’s speed. They might be running in the background without letting the user know. A user receives Software Update notifications, so he/she will be informed anyway.
  • Insufficient disk space. You may buy the latest model of iMac just to find out that it still gets slower over time without proper treatment. When an Apple device is running out of space, the issues with the performance appear, and this is the most common reason for the drop in iMac’s performance. It happens because of a large amount of data stored on the computer, and the worst thing is that a user does not need more than half of that information. The useless data is defined as junk. The experts divide junk into several categories to make it easier to understand the principle: outdated items, large files, temporary files, cache, cookies, login items, etc. just have a look at the available amount of storage and memory on your iMac. It is possible to check how much space each folder occupies by finding it on the desktop and pulling down the “View” menu -> Show Status At the bottom of the Finder window, you should see the amount of available space. It should be no less than 10% of device’s total capacity to let iMac function properly.
  • Lack of Random Access Memory (RAM). If you believe the speed of your iMac has reached the minimal level, it might be the sign of the insufficient RAM. Moreover, the computer may simply run out of RAM. It means that virtual memory took over.

Test it by launching Activity Monitor from the Utilities. Utilities are located in the Applications folder. Pick System Memory. A pie chart will pop up with the results you need. A green color identifies enough memory while a red zone stands for the serious lack of memory. Pay attention to Inactive as well.

  • High Processor Usage. In case a software/process uses plenty of iMac’s processor, a computer owner will notice the dramatic decrease in performance. Mind that many things can ‘eat up’ a lot of CPU.

Just launch Activity Monitor. Choose CPU tab this time. Pay attention to the “% Idle.” The number should not be less than sixty.

  • A variety of tools working at once. Your iMac is not Julius Cezar or Jack of all trades – do not launch numerous processes and apps at the same time. Yes, it handles several apps at a time, but turn on your sober mind. The usage of many things simultaneously often defines the limited RAM or CPU. Check this theory by telling whether the OS X Dock is a plethora of each software set up on your Apple device.
  • “Fed up” Desktop. Many iMac owners have their desktops overloaded with various items. Every item’s icon is drawn as a separate window with the brief information of the contents. There is no need to diagnose this problem with the special tool – it is obvious when the desktop is full of trash.
  • SMC/PRAM/NVRAM. iMac’s System Management Controller (SMC) might be getting out of sync, causing certain problems with performance. PRAM (Parameter RAM) or NVRAM (Nonvolatile RAM) are small memory modules, which, however, have a great impact on the system’s work.
  • Visual effects. Having various visual/genuine effects activated may slow down the work of iMac significantly. It is better to turn off the dynamic wallpapers even though they are fun.
  • FileVault disk encryption is on. Have you heard about FileVault? It is disk encryption built-in Mac operating It assists in preventing unauthorized access to iMac as the disk and files are encrypted. However, each time a user adds another function/process, the tool leads to the drop in speed.
  • What about the potential hard drive failure? The worst thing about this cause is that a user risks losing all the necessary information. Listen if you can hear any weird sounds like chunking. Moreover, it is impossible to solve the problem with the Disk Utility’s First Aid as it fails each time.

How to Speed up iMac to Save My Peace of Mind?

Now that you know the possible reasons for the drop in computer’s speed, it is time to cover the basic methods of resurrection. From the easiest to the thorniest ways – here you go!

  1. Invest in RAM/SSD. iMac owners who do not have any troubles with finances may invest some cash in additional RAM to overcome the problems with speed and lack of space in the simplest Another alternative is a solid-state disk with extra space. It is also the most expensive solution. Upgrade RAM or purchase SSD to store the huge amounts of data elsewhere – it will allow the hard drive disk function the way it should.
  2. Handle startup/login items. Is your iMac slow to boot? It can be the result of too many active startup items. Startup items are things that launch without a good reason during the startup process. Minimize the efforts your iMac invests in the bootup process by checking the full list of programs that launch together with your computer and stopping those items you do not find important.
  • Move to the Apple menu.
  • Find System Preferences and select Login Items.
  • Trim the offered list down to the applications that you frequently use when booting up. Delete the rest of the apps/processes. The nastiest programs tend to join the startup process on their own, so it is necessary to scan this list periodically.
  1. Reset SMC/PRAM/NVRAM. For SMC:
  • Shut down the computer.
  • Unplug the power cord.
  • Push and keep holding the power button. Wait for fifteen seconds.
  • Reconnect the power cord to the wall outlet. This time, don’t do anything for five more minutes.
  • Switch on iMac.


  • Turn off the computer.
  • Power the device back on.
  • Push Cmd+Option+P+R simultaneously.
  • Wait until iMac reboots. Make it possible to boot as normal.
  1. Keep it up-to-date. Make sure you have the latest version of the operating system or apps of your interest installed on your iMac. Check the manufacturer for any available updates at set up them immediately. Contact software developer if it does not help. Quit any unused apps.
  2. Take care of new user interface after the update. From time to time, it is better to give up fun and entertainment like visual effects on iMac for the sake of the speedy Switch off the special effects:
  • Go Apple -> System Preferences -> Dock -> Minimize Window Using…
  • It is better to disable various new features like FileVault or Weather by doing the following:
  • Go Apple -> System Preferences -> Extensions.  Just uncheck the things you don’t need.
  1. Wipe the hard drive. It is the measure of last resort. Start with the backup of all information. Otherwise, you will lose it by the end of the cleaning process.
  • Go Apple menu ->Restart.
  • Keep pushing Cmd+R keys during the system boot.
  • Choose Disk Utility. Push the Continue button.
  • Pick the target drive from the offered list. Select the Erase option.
  • Select Mac OS Extended (Journal). Decide on the drive’s name.
  • Pick the Erase option to start the cleaning procedure.
  1. Reinstall macOS/Mac OS X. While most iMac owners hope that reboot helps, sometimes, the only way out is to reinstall the operating system. Hopefully, you will not forget to back up things. Here is what to do:
  • Switch on/reboot iMac.
  • Keep holding Cmd+R keys. While doing that, wait for the computer to end up with loading. You should see the Utilities folder then.
  • Pick Reinstall macOS/OS X to reinstall the system, which arrived with the device.
  • Choose to Continue.
  • Pick the hard drive. Install the operating system over there. The computer will reboot once the setup process is over.
  • Push Cmd+Q. Follow the installation prompts.

How to Make iMac Faster: The Boss Solution!

The truth is that there is one more easy and effective method to reclaim space and speed up iMac except for the extra RAM/SSD. Perhaps, you have heard about various third-party cleaning applications meant to optimize Mac devices. Such utilities developed by reliable and trustworthy companies are absolutely safe to use, and, thanks to the smart algorithms of work, may not only erase all kinds of junk from iMac but also do many other useful tasks. Many external cleaning apps can find duplicates, startup-login items, app’s leftovers, temporary files, and more. After reviewing the results, a user may decide whether he/she agrees to remove those files to free up plenty of space or leave some of them.

As a result, you get a comprehensively optimized iMac for just several dollars or even completely free of charge.