17 Reasons Why Your Mac Runs Slower Than it Should

Day by day, bit by bit your Mac has got slower and slower. You don’t really notice because it has happened so gradually.

Until one day you have a chance to use another machine, that’s when you realize what your beloved Mac has become, as slow as an asthmatic ant carrying some heavy shopping.

Well all is not lost, while this list is unlikely to make you mac lightening fast overnight, one of the following suggestions may just help:

Cluttered Desktop

Having too many files and folders on your desktop can slowdown your machine. Put these files into folders in your home directory and create aliases to them on the desktop.

Corrupt Preference Files

Preference files can easily become corrupt and can make programs act weird or run slowly. If your Mac is slow using a particular application you can try deleting its preference file and relaunching he app (applications create a new file when they are relaunched if they can’t find an existing one). It’s worth making a backup of the old file just i case you lose some settings that are hard to replicate.

There are a number of great apps available that can routinely check and repair issues with preferences, caches and permissions check out my list of the best here.

Smart Playlists on iTunes

Smart playlists can make iTunes slower as they have to reload every time iTunes is launched. Disable live updating by going to File, Edit Smart Playlist and untick Live Updating.

Too Many Widgets on Dashboard

Each Widget on your Dashboard uses memory, again you can check the memory usage of your widgets by using the Activity Monitor. Remove any used or memory hogging widgets using the Dashboard control panel.

Caches, Log files and Temporary Items

It doesn’t hurt to regularly clear out built up Caches, Log files and Temporary Items an easy way to do this is to use an application like MacKeeper and Onyx.

For a full list of applications to remove temporary items, Caches and log files see: 7 Apps To Speed Up Your Mac

Wrong Firmware

Using the wrong Firmware can cause all sorts of problems, keeping your software up to date on a Mac is so easy there is really no excuse. Just click on Software Update in the Apple menu. You can also schedule your Mac to automatically check for updates, go to System Preferences and Software Update and tick Check for updates. You can change the frequency of the checks using the drop down menu.

Not Enough RAM

Software can only take you so far. Upgrading your RAM will probably give you the biggest speed increase out of any of these tips. You can use the Activity Monitor application (under Utilities in the Application folder) to check if your Mac would benefit from more RAM. Click on System Memory tab and have a look at the pie chart at the bottom. If the chart is largely red or orange you are running out of RAM. Also take a look at the Page Ins and Outs numbers, if these are continually increasing, its time to upgrade your Ram.

For some tips on how to free up some Memory on your Mac see: How to Reduce Memory Usage on the Mac

Permission Conflicts

Some issues with applications loading slowly or acting weird can be remedied by repairing permissions. All files in Mac Os X have a set of permissions, these determine which users or applications can have access to them. Sometimes permissions are incorrect and not what the operating system expects. To repair disk permissions you can use the Disk Utility app (in /Applications/Utilities). Select your startup disk and click th First Aid tab, then click the Repair Disk Permissions button.

To learn more about what Permissions are and how they work see: How To Manage File Permissions Using The Terminal

Hard Disk Is Nearly Full

Your Mac automatically utilizes free space on your Hard drive as Virtual Memory to free up the RAM. Try to make sure you have 10% free space available for this task.

To find out how to reclaim disk some space see my posts:
10 Tips to Free Up Hard Drive Space in Mac OS X
How to Manually Uninstall Apps in Mac OS X

Lots of Login Items

Removing unwanted or little used programs from your login items. To change your login items go to System Preferences then Accounts and click the Login Items tab.

Unused System Preference Panes

Clearing out unused preference panes can help free up memory and disk space, check under Other in System Preferences to see what you can remove. You can either disable it in its menu or delete it entirely by removing it from ~/Library/PreferencePanes.

Unused Applications Left Running

All running applications use up your memory and CPU resources, quit applications if you are not going to use them for a while. Some programs have memory leakage issues which means they tend to consume more and more memory the longer they are running it a a good idea to quit and relaunch these every so often.

You can view and quit all the applications and processes running on your Mac using the Activity Monitor.

Animated Wallpapers

Animated or slide show wallpaper can really impact the performance of your machine so its a good idea to turn this off.


In the latest versions of Mac OS X animations and lighting effects have become more prevalent and use even more system resources, to learn how to disable some of these effect see this tutorial.

Firefox Overloaded With Extensions

There are loads of awesome Firefox extensions so its easy to get carried away and add too many. Take a few moments to go through your Add-ons (open Firefox and go to tools then Add-ons) and uninstall any you no longer use.

Favicons in Safari or Firefox

You may see an improvement in your browsers performance by deleting your cached Favicons, for Safari just delete the files in /Library/Safari/Icons. If you use Firefox 3 read this useful tutorial on macosxhints.

Massive Mailboxes

If you have a massive mailbox with thousands of messages it’s going to take longer to load. Try to delete messages you no longer need and split larger mailboxes into folders.

Internet Settings

If you are finding your browser slow try clearing the cache and deleting your history. In Safari you do this by going to the main menu and clicking Reset Safari, tick Clear History and Empty the Cache then Reset. In Firefox go to Preferences, Privacy and click the Clear Now button. For more tips on speeding up safari see: Safari Slow? – How To Speed it Up