MacOSX Tiger doesn't have the best terminal implementation: It consumes a lot of CPU just by outputting text on screen on slower Macs. While it has since been upgraded significantly for Leopard (still CPU intensive, but not nearly as much), you may still be using Tiger on a slower, older Mac.

My MacMini PPC G4 1.25 Ghz is therefore eating a considerable amount of CPU, about 10-20%, when REBOL is doing nothing but displaying the network wait indicator in the terminal window! This is for example the case, when you are using Rugby as a server, or when REBOL/Services is running.

Fortunately this can be turned off with:

system/options/quiet: true

And then REBOL goes really quiet and less CPU hungry.

This also eliminates network access output to the console, if you want to control better what is displayed when a network resource is accessed from REBOL.

Enjoy!