I just software overclocked my Rev A. G4 400 to 533MHz! Well, sort of. Following instructions on XLR8yourmac.com I went into the Open Firmware prompt and typed in a few commands to increase my system bus from 100MHz to 133Mhz. Suddenly on restarting my G4 it happily proclaims to be a G4 533MHz in About this Mac and Apple System Profiler (10.2.5). I was in a state of shock at first - over 25%. The XLR8yourmac article stated that it probably wont work over 50MHz but I have been running it at that speed for a few weeks now with less than 1º increase in heat. Has anyone got any comments/suggestions (apart from EVACUATE!). For those interested - these are the commands I typed (from xlr8): "How to edit and store the NVRAMRC for 133MHz bus (1) Boot by holding down "Cmd" + "Opt" + "O" + "F" keys to enter the OpenFirmware terminal. (2) Enter the NVRAMRC editor. (<return> shows you should type "return" key) nvedit <return> (3) Type following script exactly (including spaces). " /" select-dev <return> 7efdc44 " clock-frequency" get-my-property 2drop ! <return> " /cpus/PowerPC,G4@0" select-dev <return> 1fca0554 " clock-frequency" get-my-property 2drop ! <return> 7efdc44 " bus-frequency" get-my-property 2drop ! <return> 1fbf711 " timebase-frequency" get-my-property 2drop ! (4) Type "Cntl" + "C" to exit NVRAMRC editor. (5) Save the script nvstore <return> (6) To enable the NVRAMRC, type this command. setenv use-nvramrc? true <return> (7) Reboot with new timebase constant. reset-all <return> "