Don't wait for Snow Leopard—slim down, speed up Leopard now
8. Remove the fonts you don't use
Getting rid of unused fonts provides both a performance and disk space benefit. Obviously, every font file is a file that takes up space. However, Mac OS X must read the installed fonts as part of the start-up and log-in process, making a large number of fonts a performance issue.
Perhaps even more importantly, all applications read available fonts at launch. This means that reducing the number of fonts can have a two-fold benefit, though it is probably most dramatically seen on older and slower Macs and may not be overtly noticeable for more recent models (unless you have an inordinate amount of fonts installed).
You can remove or disable fonts using the Font Book application included with Mac OS X (which can also be used to preview any installed fonts). Disabling a font will increase performance (as the font is essentially ignored by the computer) without removing it completely. Removing a font completely will free up space as well as improve performance.
To disable a font, select it in the font list and click the button below the list that looks like a checkbox. To re-enable the font, select it and click the same button. To delete a font, select and press the delete key on the keyboard.
You'll notice that fonts are organized by collection and family. A font family contains one or more variations (such as regular, bold, light and italic) of a single font. Removing a single member of the family removes only that variation, not all versions of the font. Font collections are organized groups of fonts that you can use to quickly locate specific fonts. The Collection column also includes an All Fonts collection, system-generated collections for specific languages and collections labeled Computer and User.
The Computer collection lists fonts installed for use by all users of the computer (those located in the /Library/Fonts folder at the root level of the hard drive). The User collection lists fonts installed for use only by the currently logged in user (which are located in the /Library/Fonts folder in each user's home folder). There may be overlap between these, depending on whether specific fonts were installed for a single user or for all users. If there is overlap, you can remove fonts from the User collection.
9. Find and remove large files and folders
This may seem like an obvious solution to slimming down the contents of your hard drive. In fact, finding and removing large files wherever possible is the best and most obvious way to recover space. The trick here is finding those large files. Files created by applications in obscure locations on your hard drive, documents that have gone from one Mac to the next over the course of several years, or folders that you just assume don't contain as much as they do are all reasons to take a good look at which files are taking up large amounts of hard drive space.
Since we're talking about files and folders that may not be obvious, consider using one of the following tools to help with the task. Disk Inventory X (free/donationware), WhatSize ($13; free trial), GrandPerspective (free/donationware) and OmniDiskSweeper (free; enhanced version $15) are all designed to look at your hard drive as a whole (rather than browsing through individual folders) in order to give you a clean and unbiased picture of your disk usage.
Once you've found the large files on your hard drive, you can choose to delete them, move them to an external drive, store them inside a compressed disk image or archive them as a .zip file.
10. Increase RAM
The final tip for this article is probably the most well-worn piece of advice for any computer user wanting to boost performance: Add more RAM. Any computer will perform faster and better with additional RAM. RAM provides working memory space for the operating system and running applications.
Leopard can allocate RAM very effectively and will swap data from RAM to the hard drive if need be, but having more RAM to work with will certainly increase performance. In particular, Intel Macs that rely on integrated graphics, where the system RAM does double duty for both regular computing and video memory, will benefit from more RAM.
[Ryan Faas is a frequent Computerworld contributor specializing in Mac and multiplatform network issues. Find more about him at RyanFaas.com.]