The simple answer is that you need to allocate more memory to your applications. If you don't know how to do it, use the Finder Help menu for instructions. Open it and type "adjusting your memory usage." Follow the instructions. You don't mention how much RAM you have, but since it's a Ti, I imagine it's no less than 128 MB--so, increase the allocated memory by at least 50% to all of your applications, and in the case of graphics-intensive apps, double the allocation. With 128 MB of RAM, I'd also turn on Virtual Memory, if you haven't done so already--do that in the Memory Control Panel. Just set it at one MB over what you have in actual physical RAM. Once you get up to a couple of hundred MB or physical RAM, you may find that VM is superfluous. Folks argue about this all the time, though.
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