In Mac OS X (10.6.3) there's a big difference in the time it takes for the computer to become responsive when you either start up your computer from cold, or or when you log out and sign in as a new (or the same) user.

By 'responsive', I mean the computer has finished to open Start-up Items, and actually opens new applications when they're clicked instead of just bouncing them endlessly in the Dock.

  1. Why is this?
  2. Is there any way to take advantage of a potential answer to 1) to make a Mac responsive faster in general? (I know, Apple probably would have already done it, but anyway...)


EDIT 1: I actually run OS X 10.6.4, forgot the last update

EDIT 2: My computer runs fine, this question was more of a nice to know type question.


If you mean that there is a difference between starting up a machine that is off, and logging in as a new user, there are a couple of factors at work.

1) When starting up, there are a bunch of system services that must start, configure themselves, and possible do some initialization tasks (check to see if files have changed, maybe check the net for new versions, etc. This generally takes time and system memory. It takes a while for things to settle down to a stable state. You generally get the login window before all of this activity is finished.

2) When you login, all of the above applies to you startup items. Also, any memory that was used for startup but is not now needed needs to be swapped out to disk.

When you logout, and then login as either the same user of a different user, the act of logging out ends off of the users programs, freeing up a bunch memory that can be used for the new user.

There is a way to take advantage of this, make your computer sleep instead of shutting it down completely. It uses minimal power, becomes usable much faster, and is in exactly the same state as you left it, with all of your programs and files open. Mac OS handles sleep/wake extremely well. About the only time I reboot my systems is when updates require it.

  • 2) sounds plausible... – trolle3000 Jul 30 '10 at 13:16

You may not have it installed, but I recently found that having Parallels 5 installed made my cold start some 7-10 seconds longer to useful state (lots of kernel extensions get loaded at start). Actually, my startup without parallels is blazing fast in 10.6.4, and apps start immediately after the desktop is displayed. It may suggest you have quite a lot of startup items / login agents+daemons. I use lingon to quickly scan the various locations along with system prefs/accounts/login items. You can also check which non-apple kexts are installed using pacifist; these can slow cold startup.

You can log your startup pressing v when you hear the start chime, and using console.app once you've logged in to see the log in detail...

  • +1 for lingon and the ⌘v - I found a Google Software Update daemon I don't recall installing.... No parallels. – trolle3000 Aug 2 '10 at 22:14

My answer to 1) is speculation - without examining your computer or knowing the internals of the 10.6.3 update it's difficult to tell for sure - but here is a (non-exhaustive) list of some things that might have happened:

a) Apple have added some new optimisations to the operating system (the was very much the case if you've updated from 10.5, though I doubt they would do so in the upgrade from 10.6.2 to 10.6.3)

b) Apple have fixed something that was breaking or failing and causing slower fallbacks to be enacted.

c) Your hard disk got less fragmented over the install. Reads will be more sequential and hence faster. This is partly what the "optimising system for installed software" stage you may notice during installs is doing.

d) Your permissions got repaired over the install.

For part 2), obviously you can't do much about a) or b) unless you go digging around in the Darwin source code.

c) You can do yourself, although Apple claim it won't make much difference. Either Google for a free defragmenter or do a poor man's defragment by moving files to an external disk, then moving them back.

d) Open up Disk Utility (/Applications/Utilities), select your start up disk and click "repair permissions". It's no bad thing to do this every month or so, and it can stop all sorts of odd behaviour.

  • +1 for repair permissions, didn't know about that. – trolle3000 Jul 30 '10 at 13:16

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