What slows a Mac down?

Question from the newbie (I had recently first anniversary of having switched to the Mac) to the experienced: What generally slows a Mac down? What are the no-nos? Where to look first? What to consider?

I have an iMac, 1 GB memory, and my impression is that in the last few weeks, it responds slower and slower. Applications start slowly. The dashboard takes loooong to come up when I call it the first time in the morning or after several hours when I did not need it. I sometimes had even moments when what I type appeared one. letter. after. the. other… Experiences Windows-User that I am I did a restart then and that fixed it indeed.

Any hints welcome… :cry:

it could be a variety of things. The most obvious is you only have 1Gb of memory 2Gb would be better. Don’t go for the Apple branded stuff, use either Kingston (not value ram) or Crucial which costs much less.

Something else you can try is to run the maintenance routines. These clear out temporary files, clean caches and so on. You can do this from the command line but it’s much easier to use something like Onyx: titanium.free.fr/pgs/english.html

Be careful to get the correct version for your operating system. I think the latest one is for Leopard ONLY.

Normally on a Unix system the maintenance is done automatically at around 2 am, but if your machine is asleep this won’t happen, so Onyx fills the gap.


Sounds like you just accumulated ‘memory crud’, which affects all computers to some degree, as memory gets locked up from certain apps not releasing it correctly when they’re done with it. And yes, the best solution to that is a restart (actually, just a logout/login will often do the trick, too).

That said, you should consider upping your RAM, especially if you’re on 10.5. 1GB is usable, obviously, but you’ll get much better results, and be less vulnerable to memory crud, with another gig of RAM in there. You can pick up 1GB from Crucial for less than 50UKP including postage (you’re in Germany, right? No idea what it is in Euros, sorry - but suffice to say they’re cheap but very good).

True. I use YASU for this myself, but they all do much the same thing.

Actually, it will. Since 10.4 OSX now runs daemons that watch for the cronjobs. If your computer’s asleep at the job’s scheduled run time, OSX will realise this when it next wakes up and run the routines then instead.

How much diskspace do you have available? It is generally recommended not to run Mac OS X with less than 5GB of available space. If that’s not a problem then I would suspect your hard disk is failing–backup everything now. In my experience OS X is fairly tolerant of failing drives, so when it finally goes it will go suddenly and forever.

Oops. I have a one-year-old iMac and still 111 GB free. (Of course I backup regularly.) Aren’t there any tools available to check whether the hard disk is OK or not? Before I carry my computer some hundred kilometers to the next Apple store to have it checked and laughed at me for being hypochondriac… :open_mouth:

  1. Run Disk utility once a week to verify file permissions.
  2. If you sleep the machine overnight, Quit all apps. They eat memory.
  3. Check for Software Updates: installations often optimize the disk.
  4. Update all apps to the latest versions via MacUpDate or VersionTracker.
  5. Avoid leaving too many apps open at the same time.
  6. Backup to an external drive, because you may have a hardware problem.
  7. Consult the Apple discussion boards about your problem.
  8. Google “slow iMac [supply the processor ID from About this Mac]”
  9. Go see that Apple Store. I once took in a laptop that “wouldn’t boot”
    Solution: the screen display was turned down. No one laughed, nor charged me.

Good luck!

I bought a refurbished MacBook about a month before Leopard was released and I can already see that I’m going to have to go to 2 Megs of memory. I still rarely see the spinning beach ball but some things are slowing down a bit. Like everyone says, “OSX loves memory.”

There is a free, handy Widget, called Maintiget that allows you to run the daily, weekly, and monthly maintenance scripts whenever you want. It lists the last time they were run and allows you to run them on command if you are overdue. I’ve heard that if your machine is in sleep mode at 2 AM that the scripts will run when you awaken your machine but I’ve been a week or two overdue on the monthly script and nearly a week overdue on the weekly script, so it does come in handy.

Agree with Druid’s checklist. The problem you are experiencing could be minor (like a cache issue, or excessive virtual memory usage due to leaving it on for months on end), but the only times I have had a Mac suddenly slow down like this without any major hardware change or disk space usage is when the drive has fatal errors. Finder starts to behave erratic and slow; applications take forever to load; even windows when clicked on can take a while to come to the top. This usually indicates a serious problem that should be fixed as soon as possible. If you do come across a fatal error, back up your information immediately before doing anything else. That cannot be stressed enough. I have witnessed occasions when attempting to fix errors simply causes the drive to fail requiring a full reformat and installation. Then proceed to troubleshoot using AppleJack, Onyx, or Disk Utility, Disk Warrior—whatever it takes. You might be facing the need to re-install though. Good time to upgrade to Leopard if you haven’t already. :slight_smile:

Hopefully it is just a cache or font problem, though!

Sometimes I have a process that grabs a lot of CPU cycles on my machine (iBook G4 running Mac OS 10.4 Tiger, with 1.5 GB ram). Then everything turns to molasses: lots of spinning beach balls, programs are very slow to launch or respond to mouse clicks, etc.

You can check what programs (usually hidden, background processes) are eating up your CPU cycles by opening Activity Monitor, which is in the Utilities folder. It has lots of controls and monitor views to show you what is happening. A floating CPU window (go to Window>Show Floating CPU Window) tells you how much of your CPU the computer is using at any time. When the CPU is maxed out, everything slows down.

The program also shows you, among other things, a window with a list of active processes, together with how much CPU, memory, virtual memory, etc., each process is using. Sometimes it’s useful to kill (Force Quit) a process that is hogging too much CPU. Select the errant process in this window and click the Quit Process button. Then everything bounces back to normal speed. Of course, you won’t want to kill necessary processes, like kernal task. Other, more savvy users may be able to tell you which of these processes will restart themselves as needed, which are likely to be culprits, and which ones to leave alone. Checking Activity Monitor before and after a restart will often give you data for a good guess about what process is out of hand.

John Robert

I agree that it sounds like the hard drive is signaling trouble.

Though I always max out the memory on any new Mac as much as possible, it allows them to age gracefully.

Another tip is to keep the clutter off your Desktop. I tend to throw things there (somewhat like real life) and so I created a bunch of folders on my harddrive, with aliases on the desktop. I can actually find things that way.

I’ve had some slowdown and disk thrashing with my 12" Powerbook. It’s only carrying 768 MB of RAM, but that hasn’t been an issue until recently. I suspect Safari and Flash Player have something to do with it.

This is something I’ve heard before, not so much recently. I still have no idea why storing files on your desktop should impede the mac’s performance? Anyone?


It’s the icons. Ten or twenty files won’t matter but if you have more and they are pictures it can measurably slow performance as the system has to render the previews every time something changes. I had a client who by mistake dumped several hundred jpegs on his desktop. It literally brought the laptop to its knees—every time he rebooted the machine appeared to lock-up when the desktop was displayed. We had to boot in single-user mode and use the terminal to move the files to a folder to solve the stall.


But if its the icons, then shouldn’t having a hundred icons in a folder also bring the mac to its knees? I can dump thousands of jpg-files into a folder and not notice any speed impairment.

What is special about the desktop?


Your folder is not open ALL the time, whereas the desktop is always open. This means that your desktop rendered on every screen redraw.

Not sure if that makes sense or not.

I once accidentally moved a bunch of files to my desktop while pottering around trying to figure out what had slowed my PowerBook down (turned out to be a bad hard drive). It was a nightmare that lasted all day.

Do you keep a window in icon view on that folder open all the time?


Well, no, but why would the Finder-window need to be open over a longer period? Does the effect somehow accumulate? Some cache? VRAMblabla?

I seriously doubt that cleaning up your desktop will do much. That is, unless you’re keeping several hundred icons there, cleaning it up will "marginally speed up the performance of your Mac by cleaning up your desktop icons. Each icon has to be refreshed when you look at your desktop so this takes away from your performance. " http://guides.macrumors.com/Enhancing_Performance_Of_Mac_OS_X#Clean-up_your_desktop

I have tried a few hours now with a Finder-window open with 1012 jpg-files IN VIEW on the largest icon preview. There is hardly any effect on performance until I try to mess with the actual window. But e.g. working on scrivener, firefox, photoshop, I notice no difference. Because the icons are covered by the application in use (like the desktop icons are…), I guess. However, when I try to work in say Photoshop with the 1012-icon Finder-folder in view, I notice nothing either.

On a 2.2 GHz MacBook 1 Gb RAM.

Anyway - the other tips on that macrumors.com page will help you vastly much more than cleaning up your desktop. However, a clean desktop might speed up your brain’s time needed to process the mangled mess presented to it… :slight_smile:


The rules about when and how the OS renders (draws) windows is significantly different from those used for the desktop (the root window). The impact will be dramatically different depending on hardware, the way the icon is specified, and other system level settings (eye candy).

Your comparison is like comparing 1200 people on speed boat to 1200 people on a freighter. Sure both are boats full of people, but only one is designed to get people moved quickly.

Your window full of icons is the speed boat, where the desktop (window manager root window) is the freighter.

Hope that helps a little.