iCook iBook Overclocker Copyright (c) 2004 Patrick Swieskowski This could potentially damage your computer. Use at your own risk. To install iCook run the "Install iCook.pkg" installer. iCook is a kernel extension for OS X that lets users control the speed of their IBM 750FX processor. All iBooks with 16MB or more of video RAM use the 750FX and should be compatible with this software (Note: This does not include the iBook G4). It creates a new sysctl "hw.cpuspeed" that the current cpu speed can be read from and new cpu speeds can be written to. It supports speeds from 300-1200 MHz in 50 MHz increments. For this to work iCook must disable the kernel's own internal control over the cpu speed. This is done by patching the kernel image in memory. No permanent changes are made and a reboot will bring the system back to normal. IMPORTANT: A side effect of this is that the Processor Performance setting in OS X's Energy Saver preferences will no longer function properly once iCook is loaded. It is recommended that this be set to Highest before using iCook. This will configure other system components to work with a high-speed processor and allow you to get the best performance from your system. The Reduced setting works with iCook, but the system will start to become unstable at a lower speed. Using the Automatic setting with iCook is just a bad idea, don't do this. The only interface to iCook is through the "hw.cpuspeed" sysctl. This can be used most easily through the command-line program "sysctl". Simply open up a Terminal (usually found at /Applications/Utilities/Terminal) and type commands similar to those listed below. Example Usage: -- Load the iCook kext, this must be done before any other commands -- $ sudo kextload -b net.swieskowski.iCook kextload: /System/Library/Extensions/iCook.kext loaded successfully (if the kextload fails you probably do not have a 750FX processor) -- Check the current CPU speed -- $ sysctl hw.cpuspeed hw.cpuspeed: 700 -- Set the CPU speed to 800 Mhz -- $ sudo sysctl -w hw.cpuspeed=800 hw.cpuspeed: 700 -> 800 For more information see http://www.swieskowski.net/icook/