Like many Mac users out there, I find some of the Widgets available in OSX 10.4 (Tiger) fairly useful. However, everyone should be away that using them doesn’t come without a price. That price is paid in memory (RAM).
The average Widget uses 25-30MB of RAM, even when Dashboard is NOT active. You may want to be fairly selective on which Widgets you choose to leave open, and close down the ones that you don’t use very often.
You can check you memory usage through the Activity Monitor.app located in your Utilities folder. For an even easier way to continuously monitor your system resource usage, check out MenuMeters, an awesome little Freeware utility that places customizable system resource information in your main menu bar.