How to speed up a sluggish Mac

Wil Limoges shares his tips for speeding up a Mac that seems bogged down by performance problems.

You've got a slow Mac. No problem! I've got a couple of quick and easy tips for revitalizing your Mac.

The first place I always like to start when I'm experiencing undesirable performance is with my hardware configuration. With each generation of Mac OS X, Apple increases most of the system requirements and for good reason. Because applications are hungry for memory so they can perform more complicated tasks and often take up more space. Coincidentally, memory and hard drive space are often the culprit for systemic slowdown. Modern Macs (Intel Core2Duo and greater) are generally packed with an adequate amount of power, but depending on how you use your computer you may experience varying degrees of performance. I personally abuse my Mac. I often have twenty or more applications open at any given time, leave it on for months at a time only rebooting when an update is available, and pack my drive full of large graphic and video files. I'm a perfect candidate for poor computer performance; however, I also took my behavior into account when purchasing my last Mac by making sure I had ample memory and plenty of hard drive space.

Hard drive

Hard drives are more often a reason for slow down then any other component on a Mac in my experience. If a drive is full it prevents Mac OS X from being able to quickly swap information from memory to the drive when needed. If your cursor is a spinning pinwheel more frequently than it is an arrow, then there is a good chance your drive is either full or your drive may be experiencing a mechanical failure. To check your drive's capacity and space used, open up the Finder, navigate to your hard drive, select it, click File from the menu bar, and click Get Info. The Get Info pane will show you both the capacity of your drive and how much of that space is being used. If you have less then ten gigabytes then its very likely this is what is slowing you down. Purging files that you no longer need or migrating them onto another drive will help get you back up to speed quickly.

Upgrade your memory

Two gigabytes of memory is really the least amount of memory you can get away with under any modern version of Mac OS X; however, if you are at all like me and push your Mac pretty hard, then you should consider upgrading your memory. The more you add, the less likely you will be to experience performance issues.

Purging unnecessary files

Sometimes the slowness that you are experiencing is the cause of some troublesome file located in hard to find places. There are some easy ways to clear away some of these issue just by running through a few simple steps. PRAM reset is one of the first things that you can do to improve system performance and clear out potential issues. Resetting your PRAM clears out caches on your logic board that can sometime be responsible for a sluggish system. To reset your PRAM: reboot your computer and immediately after your Mac has shutdown, hold down [Option] + [Command] + [P] + [R] together during the boot process. After a few moment your Mac will reboot again after which you can release those keys. You have now successfully reset your PRAM.

Safe boot

Starting your Mac in safe boot will clear out your cache stored on your hard drive. This process can take a bit more time than resetting your PRAM but is another way to purge some files that can sometimes cause performance issues. To safe boot, simply reboot your computer and hold down the [Shift] key during the boot process until you reach the login screen. If you succeeded you will see the words Safe boot within the login pane. Log in and reboot to complete the process.

Archive and install

If things don't seem to be speeding up at this point, don't fret, there are still a few other things you can do to get your Mac back to factory. An archive and install can help to remove the gunk under the hood. Before proceeding with an archive and install, I highly recommend a backup of all your files just to be on the safe side. If a drive is too full or failing due to mechanical failure, you could be left with a machine that will not boot after running an archive and install. Also note that running an archive and install is different for Leopard, Snow Leopard, and Lion.
  • For Leopard you need to start the installation process and when you are asked to select a volume, select it, and click the Option button located at the bottom of the installation pane. From here you can select Archive and Install.
  • For Snow Leopard and Lion, each installation defaults to Archive and Install. Once you've completed the archive and install process, log in and be sure to remove the Previous System folder from the root directory of your hard drive.


This is by far my favorite way to speed up my Mac but also is the most risky. This time, however, I'm not just suggesting that you back up your drive first; it's required for this method.

  1. Assuming you have your drive backed up, you'll want to boot from your copy of Mac OS X or with Lion from Recovery Mode by holding down [Command] + [R] during boot.
  2. After booting, open the Disk Utility application on your installation disk and select your installed drive (not the partition).
  3. Click the Partition tab, and create a new single partition under Partition Layout. By creating a single partition as apposed to just erasing the drive your Mac will rewrite your partition tables eliminating any potential issues that could result from use over time.
  4. Click Apply and reinstall your Mac.
  5. Once you've completed installing your Mac, reboot and create a temporary admin user account with an easy-to-remember user name and password.
  6. Once you've logged in, connect the hard drive that you used to back up your Mac and navigate to the Users folder.
  7. Copy your User folder that you backed up to the local Users folder of your Mac. You'll be asked to enter you admin password. Enter the password and allow the drive to copy over completely.
  8. Once the process has completed, open up your system preferences from the Apple icon of the menu bar and click on Users.
  9. Create a new user and be sure to give it the same exact short name that your home folder was named and password from your previous installation and Click Create User.
  10. Mac OS X will notify you that a home folder with that name already exists, would you like to use it? Agree and your previous account from your backup will be fully restored on a fresh system.

There is one drawback to this method, which is that you will be required to reinstall all of your applications, but I always find that this is an opportunity to only install the applications that are needed and to leave out any of the unnecessary ones that I rarely use, making for a beautifully reinstalled Mac.


Wil Limoges is a Louisville, KY freelance web designer and Digital Savant at the vimarc group. He has had the pleasure of working for Apple as a Genius, loves science, and aspires to make great things!


First of all find out the reasons behind your mac slow performance that may be so much duplicate files, junk files etc. To boost up its performance, you will have remove all garbage from mac computer. no worry, just try the tidy up mac tool. it is the best tool that will help you to get rid of slow performance of your mac. http://www.tidyupformac.net


So today it took me a stupid amount of time to work in photoshop so I got online to see any suggestions. I found site and Purging Unnecessary files/Safe Boot. After that, my sound quit working and licenses stopped working. How do I go back and fix it. I have an Imac and it has internal speakers and it says, "No devices found." Please help!


Dear Editor, I wish to convey my thanks to your article which really helped me get some great knowledge about speeding a slow Mac OS X. To speed up my Mac I followed the steps you suggested and got good results. Also I got to know that considering a speed up Mac OS X software is also a good alternative which can easily list all the unnecessary files within few minutes. The later can be deleted to speed up Mac OS X.


Onyx will speed up a mac but to run the entire litniy of scripts it will take about 1-2 hours depending on the system. (http://www.titanium.free.fr) but it does

Domino Chance
Domino Chance

I installed Kodak printer drivers and my partner's mac slowed to a crawl. The AIO was eating up almost 90% of her CPU time with it's Bonjour settings. Since she was plugged directly into the printer I could delete the bonjour settings and speed up her mac.


Just after writing my suggestion I checked on Seagate and there is a SD28 firmware for these drives. In other words, just make sure you have the latest firmware for this drive.


The article has good ideas but I have to agree that re-installing on a Mac is a very rare event and relatively time consuming (to the other options). Now my 2 cents: 1) Use OnyX a well tried, free and frequently updated utility that will clean cache files, run some UNIX maintenance scripts and even has some Finder default options. It is available at http://www.titanium.free.fr/ and pretty much everything you might need in that area. 2) Upgrade your hard drive. If you have a MacBook you absolutely have to try Seagate Momentus XT Hybrid hard disk. It's a combination 7200 RPM disk with built-in flash memory that will knock your socks off. Just make sure it has the latest SD25 firmware installed as some issues were reported with the original firmware. We have installed a dozen of these at our office's laptops 8 PCs and 4 Macs with not a single issue. Overall performance gains are very good but on booting and on virtual machines is simple astounding. 500 GB will cost you USD 99.


Most of the points here are good, but the "Archive and Install" and "Reinstall" suggestions are *almost never* required in Mac OS X, and highlighting them as troubleshooting steps for performance is likely wasting a lot of people's time. The whole "wipe and reinstall" is necessary wisdom from Windows troubleshooting that is absolutely erroneously applied to Mac OS X, and it will rarely if ever will make any difference on a Mac. Archive and Install will only make a difference if you've somehow hosed up the internals of Mac OS X, which is not something that will normally happen absent some other hardware failure. Other important points are missed. Performance issues due to hard drive issues can often be detected by opening the Console, selecting the "All Messages" log and then filtering for "i/o error". Any drive throwing I/O errors into the log should be immediately cloned (if possible) to a new drive using the free utility Carbon Copy Cloner (http://www.bombich.com/) and then replaced with the new drive. SMART errors will sometimes indicate a failing drive, but the absence of a SMART error doesn't necessarily indicate a healthy drive (there are often false negatives with SMART). You can check the SMART status of a drive in Drive Utility in /Applications/Utilities. Click on the disk media (above the hard disk name) and then look for "SMART Status" at the bottom: if the status is anything but "Verified", clone and replace the drive immediately as mentioned above. A great free utility for ongoing monitoring of hard drive health is CoreCode's SMARTReporter (http://www.corecode.at/smartreporter/), which constantly monitors all of your hard drives for SMART errors as well as your logs for I/O errors, reporting either with your choice of a popup, an email, or by running another application. It will also check any software RAID1 arrays that you may have set up in your system, making it a truly universal disk health utility. A more comprehensive SMART utility that is great for proactively testing a drive is Volitans Software's SMART Utility (http://www.volitans-software.com). This application's Long Test can be run live on your hard disk in the background and will detect any bad sectors on the disk. More than a few, or an increasing number, indicates that the drive should be cloned and replaced. One other rare but possible performance issue to check is antivirus software. As more Mac users being to use antivirus software (either just to be as safe as possible or to not pass on Windows malware that they may come across), it's possible for the "Live Scanning" features of these utilities to take a big chunk out of performance. If you have antivirus such as Sophos installed and something is taking a long time that should generally be quick, try temporarily turning off the live scanning capabilities and see if it improves performance. If things are running a little too slowly and you're running a 5400RPM hard drive (you can check in System Profiler and Google your drive's model number to determine the RPMs), an easy and relatively inexpensive way to increase performance as well as give yourself a space upgrade is to replace your drive with a new, fast one. Any 7200RPM drive will give a pretty significant performance boost over a 5400RPM drive, especially for FileVaulted laptops and others that do a lot of disk I/O. A great source for drives along with Mac support expertise is Other World Computing (http://macsales.com/). To replace your drive, hook up the new drive to your Mac (there are various ways, including my favorite, the NewerTech Voyager, also available from OWC), clone to the new drive using Carbon Copy Cloner, then just replace the old drive with the new one and you're in business.

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