10 Years ago when I was new to the forums here on MacRumors, I built a G4 tower using spare parts from various sources on the internet in order to further transition my way away from windows PCs being used at home. Essentially it is a Dual 533 Digital Audio, housed in a quicksilver case. Somehow I ended up shopping for the parts when they were being liquidated by Apple Spare parts vendors, and scored a brand new case, logic board, and power supply for Recently I had started to heavily use this machine again, putting it to work transcoding video files down to smaller versions to be used on my various iOS and iPod devices in my little collection. After unplugging this computer to move it to a new location, I am now faced with a G4 that will not power up. I am aware of the button on the logic board to reset the power management, as well as other tricks to get it to boot (I had to do this when I built the system), however, I believe my issue is actually the power supply, due to some other issues I have been having recently, so I will need to source out a replacement. So Finally the question! I am curious what others on here are doing with machines of this era to keep them kicking, and I am curious what the best upgrades are with regards to upgrading the internals? I have considered upgrading the processor to one from a Quicksilver G4 (yes I know I need to bring it power), but have also considered used processors from OWC and the likes to get it over 1 Ghz. I love having dual processors, and want to take advantage of the OEM dual processors if possible, however options for dual processors faster than 533, and compatible with a DA or QS are more rare. I remember reading that the Dual Processor G4 systems are essentially 1.5x faster than their single processor clock speed would indicate. Meaning I would need to have a single core with speed of 800Mhz + to gain meaningful speed improvement over my current setup. Is this even close to being accurate logic? I would hate to buy a used single processor, to find myself with a system no faster, or quite possibly slower than my current Dual 533. Thanks for any feedback on other's working setups!