Seems theres the zdnet application that doesn't run in El Capitan and I can't find anything else out there... so, what is the deal? My 2.66 quads are what they are?
I saw the thread title and came here to post the ZDNet recommendation. So... not sure what to tell you. That box was EOL in 2007, so I doubt anyone's been working on an overclocking utility lately, but I could be wrong. Sorry I couldn't help.
im fairly shore that app was not good, the clock speed (ie like date and time internal clock) of the mac was dependent on CPU speed so when you overclock you brake everything dependent on the internal mac clock.