SCROLLING SPEED: speed up your scrolling by as much as 50% by turning of Font Smoothing in the Appearance Control Panel (Mac OS 9.0, 8.6 or 8.5).
STARTUP SPEEDUP: Turn off the memory diagnostic and your STARTUP time will shorten. (Open memory Control Panel with Option and Command key held down.)
WAKEUP FASTER: Turn off AppleTalk when you don't need it and your PowerBook will wake up in 6 seconds instead of 15 seconds.
PHOTOSHOP OPTIMIZATION: You want it to use all the RAM available. Check your "largest unused block of memory" by selecting "About This Computer" under the Apple menu. Then do Get Info on Photoshop, setting the Preferred Memory to all but 10% of the remaining unused memory. Also, turn off Virtual Memory and set Disk Cache to minimum. Photoshop has its own scheme for both.
Another way to figure the Application Size for Photoshop. Find the largest Photoshop document you plan to edit. Multiply the size of that file by 6. Set Photoshop to that memory size. Don't have enough memory? Get more. There's no substitute for RAM if you want ultimate speed.
BROWSER TIPS: If you are trying to browse the net with very little RAM in your Mac, you might try the iCab browser. It uses only 2 or 3MB's. That's only a fraction of what the bloated Explorer and Communicator applications use and much better than listening to your Mac's hard drive thrashing while virtual memory tries to compensate.
A lot of folks have reported nasty problems with Explorer 5.0. Some have gone back to 4.5 until 5.5 is out. Others have gone to Communicator 4.7. I've found nasties with all three. Some folks use RAM disks for the cache. Some set the cache to zero and let the server cache the pages.