Prior to installing Leopard, my iMac would startup in just a few seconds. But, after the upgrade, startup has been almost as slow as with my Windows XP startups. This happened despite the fact that my iMac has plenty of horsepower to handle Leopard: it has 2GB RAM and is only 9 months old, so it is not an ancient, under-nourished system that could not handle Leopard.
I did a few simple things that improved the startup a lot.
The first “trick” I did was to clean up the Documents folder. It had hundreds of documents and pictures and zip files in it. I simply added a couple of new folders under the Documents folder, and dragged the docs and pictures into them. I used VariousDocs and VariousPics as names for the new folders: no doubt you can be more creative if this “fix” is appropriate for you. If this helped (and I think it did) it would be because Leopard reads the Documents folder on startup, and starts associating icons with the documents in it, to give you a quick response when you click on the Documents folder in the Dock. I do not know that this is the case, but it seems reasonable to me.
The second trick was certainly helpful: I went through my Library and deleted all traces of programs that had previously been “uninstalled” or that I no longer used, and I spent time going through the caches to clean out anything that was not supposed to be there. In my case, there were a lot of instances of Missing Sync items in the caches, a utility I had installed sometime back and but that has not yet been updated to work with Leopard. I had spent time cleaning out the Library before updating to Leopard, but I had not been as thorough as I thought I had. A second effort paid off.
The final trick was to download and run TigerDock. This utility removes the 3D effects from the Dock and turns it back into a Tiger-like Dock. All that it does is to run the following commands for you, which you can run yourself from Terminal:
defaults write com.apple.dock no-glass -boolean YES
killall Dock
[Courtesy of Wired via Lifehacker.]
To reverse the effect (to return to the 3D Leopard-like Dock), just change the “-boolean YES” of the above to “-boolean NO” and you are set. TigerDock actually adds one other trick: the glassification/de-glassification of the Dock. I have not used that part, nor do I plan to.
Of course I cannot guarantee that these tricks will speed up Leopard for you, but they did for me. I was disgusted with its startup until going through these “tricks” today. The startup still does not seem as snappy as it did with Tiger, but it is much improved.
Update:
I ultimately did a clean install of Leopard, which is detailed in this article. The new article also discusses the true cause of the problem with the lingering blue screen on some Leopard upgrades.