What are the best-resources to fine-tune Mac OS X (10.6.4, Snow Leopard on a 13in unibody MacBook). I've been a long-time Windows users and bought a Mac couple of years ago.

In Windows, I could have cleaned registry, removed un-necessary services, use msconfig to tune etc.

With the usage and all the Apple updates, looks like the OS is sluggish. Any pointers to resources online will be helpful. I tried clearing Browser cache, flush DNS etc.


Thanks for the responses, I have used Onyx and it helped ..

I have also replaced hard-drive with SSD and the machine is much faster. (Unibody 13 inch Macbook 5,1 ~ 2008)

And upgraded to MountainLion and enabled SSD Trim.

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  • ha.. just don't try looking for defragmentation tools, also browser cache / dns flush does nothing for performance, if anything those two speed up performance by doing local caching. Your machine generally should not feel sluggish, this isn't Windows, it has unix underpinnings and better memory management etc. – Jakub Jul 30 '10 at 19:33
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    I had gone just about 3 years without doing a fresh install of the OS and my hard drive's fragmentation was pretty bad. A poor-man's solution is to use Carbon Copy Cloner to make a copy of your drive on an external drive, format the internal one, and then copy everything back over. Also, doing a fresh install of OS X and moving everything back over is ridiculously simple compared to Windows. Took me about 4 hours to get back to the way I had things before. – donut Jul 30 '10 at 23:06

10 Answers 10


This is the article you are looking for.

If your OS feels unusually sluggish, it may be a problem with a process you don't know is running (like mdutil indexing for spotlight search), lots of disk thrashing due to a memory shortage, or perhaps some misconfiguration is causing lots of errors.

I would check the Console application to see if there are unusual messages. And use the Activity Monitor to check if some process is taking up too much processor time.

Most of the time additional tuning of Mac OS X is unnecessary, as long as the regular maintenance scripts are running properly. The best way to increase performance is to buy more ram and/or a solid-state drive.


Skip repairing permissions; 99% of the time it's just voodoo done by people who want to think they're accomplishing something.

Given that you say your Mac is a couple of years old, I'd bet that you're maxing out your RAM. Unlike sacrificing a goat or repairing permissions, adding RAM actually works to speed up Macs -- more than you might think.

[edited to add the following]

Two other questions whose answers you might find helpful: Does more RAM on Mac really improve performance? and Memory upgrade to 8GB on unibody MacBook.

  • Or get a faster HD. Either a Seagate Momentus XT or OWC's SSD, whatever you can afford. – churnd Aug 1 '10 at 17:35
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    Repairing permissions is often useful and a solution when system folders have their permissions corrupted. But I think you're right when you say it doesn't improve performance; even then it shouldn't be regarded as "voodoo" as it solves many severe problems. – Vervious Aug 28 '10 at 4:20

A good, but simple, Mac clean up is repairing permissions. Open up Disk Utility (in /Applications/Utilities), select your start up disk and click the repair permissions button. It'll sort out mismatched permissions on files installed by Installer and can solve a fair amount of odd behaviour - it does no harm to get into the habit of doing it every few months.

Apple have deliberately minimised the amount of tuning you can (or need to) do from the GUI, so most other stuff will need a separate application or will require delving into the Unix underpinnings.

Although mainly for eye candy rather than performance tuning, TinkerTool is a good start. It makes available a whole lot of hidden preferences, but also makes it easy to revert to defaults if you do something silly.

Another good place to look for power user tips with OS X is Mac OS X Hints. It has all sorts of hints on the more arcane features of OS X, and I'm sure there will be several on tuning for performance.

  • 3
    Repair Permissions: the zap the PRAM of the 21st century. Pfft. – ghoppe Jul 30 '10 at 20:17
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    Repairing permissions without having a very good reason can actually harm things more than help them. – churnd Jul 30 '10 at 20:40
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    It won't generally harm anything, but in most cases, it's not terribly useful, either. It also only works for software that was installed via the Installer app, so other files are unaffected. – mipadi Jul 31 '10 at 1:38

Try OnyX's maintenance tools. It allows you to run a lot of maintenance/cleanup tasks at once.

This includes the daily/weekly/monthly maintenance scripts built into osx. Additionally it allows you to clean a few caches and tweak a lot of settings. Too much to describe here.


I recommend CleanMyMac.

It's not a freeware, but I'm using it for a year now and I'm very happy with it.

Here is a screenshot of its interface in order to have a preview of its features :



Along with the other good suggestions, I've found that the main thing that slows down my Mac are simply things that start up when I log in. The best app for discovering these things has been the Consultant's Canary. A little thing that pops up a Terminal window and lists out all the different things that may be starting up when you log in or when certain apps launch (i.e., browser plugins).


There is really not much you need to do. As others have already pointed out, Mac OS X is a unix system underneath, and a lot of the maintenance needed is done automatically on a set schedule. The HFS+ filesystem is journaled which helps prevent file corruption & does not need to be defragmented like NTFS. Apps are mostly self-contained, & there is no registry to worry about.

If you really look at most of the 3rd party "maintenance utilities", all they really do is delete temp stuff.

The majority of the time, if your system becomes unstable, it's because of a 3rd party program.

  • Why do you think that HFS+ does not need defragmentation? – Mike L. Aug 1 '10 at 14:04
  • osxbook.com/software/hfsdebug/fragmentation.html Scroll to the bottom if you don't care for the technical details. This guy is a Google engineer, and probably has more in depth understanding of OS X than most. The sad thing is that 3rd party software vendors are taking advantage of Windows users migrating to OS X by saying you need all these 3rd party utilities to keep OS X properly managed like you did in Windows. The reality is most do nothing, and in some cases actually hurt you. – churnd Aug 1 '10 at 17:31

I highly recommend Maintenance, from the makers of Onyx. Onyx is pretty good and can also tweak hidden system settings, which Maintenance can't, but Maintenance is strictly focused on system cleanup, running scripts, and deleting unneeded files, kinda like CCleaner. It can repair permissions, rerun system cleanup scripts, verify volumes, check S.M.A.R.T. status, clean the spotlight index, clean DS_stores, clean system caches, and more. The documentation also explains EVERY feature it has.

I'd recommend giving Maintenance a whirl, and looking at Onyx if you need something that's not in Maintenance or if you also would like to enable hidden system features. However, Maintenance does have system cleanup stuff as well.

  1. You can try to use Onyx (http://www.apple.com/downloads/macosx/system_disk_utilities/onyx.html)

  2. Manually started periodic scripts (run with superuser from Terminal.app) can help also:

sudo periodic daily

sudo periodic weekly

sudo periodic monthly


As well as the options posted here. If it's still a bit sluggish consider adding more RAM and upgrade to an SSD drive. It'll make a huge difference.

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