David, Thank you very much for the input. I had a recent sad adventure with a PowerLogix 1.35 GHz that I've previously comented here @ the List. Basically, I would like to know if you've already performed hard testing with the Cube's hardware components, such as USB and FireWire ports. My PL was working OK except for the FireWire connections, where a write/read from external and internal hard disk drives would lead me to corrupt every single hdd attached to that chain. Plus, what is your info in System Profiler? Does is recognize the new CPU? Do you still run Mac OS 9? Is the patch complicated to apply or is it somehow risky? I really don't want to go through the sad story once again. Best, LM P.S.: If you're interested in reading about my PL adventure I could send you a direct email. >>> David.Lambourn at blueyonder.co.uk - 2004/09/30 09:17 AM >>> Hi Luis, I fitted one last week. I am very pleased with it. My Cube had a 500Mhz chip. The instructions were OK. The procedure requires that you first upgrade the firmware. A separate CD is supplied for this. I had a self-inflicted problem with this stage - I still use my old SE keyboard through a Griffin iMate in preference to the standard USB keyboard - the firmware update does not happen properly with this KB but worked first time with the USB KB. I have no thermometer to measure temperature accurately, but my subjective judgement is that, if anything, it runs cooler than the 500MHz chip. I concede that I might have a vested interest ! I see no reason not to recommend the chip - as I said. I am very pleased. All my software now runs natively in MacOSX, and for the odd occasion I am content to use Classic - so I have not bothered to run the OS9 software boot patch, which comes with the CD. For those wanting to boot regularly in OS9, there would appear to be no problems other than the certainty of losing the boot patch when Zapping PRAM - which means a reboot in OSX and re-running the patch before rebooting in 9. Happy to answer any further questions. Oh yes, you'll get a quality screwdriver ut of the deal! David