Hello all, first post here. First attempt at building ANY computer. I've been a professional mac guy for 20+ years though. Handy in the shop, I have lots of tools. What I don't have is a handle on things that long time builders probably know in their sleep: how to determine cooling needs. I'm going to put an i5 on a M-ATX motherboard off the compatible list, and I'll use onboard graphics at least initially but never plan to go heavy duty on a GPU. Not planning any need for it as this system will mostly run Indigo home automation software and iTunes whole house audio via AirPlay. I'm replacing a Late 2009 Mini that's stock and almost keeps up with my needs, so you can see I don't require a lot. I've poured over the PowerMac G4 builds here and gotten a lot of good ideas and insights. I've also stripped down the old G4 case to get familiar with its layout. I have no need for an optical drive at all in this build, which makes lots of thing easier. My goals with this build: Minimal cutting or drilling. Preferably zero mods to the outside of the case aside from the IO panel on the back. Reuse the case's drive locations, PSU location, hopefully even original case cooling fan location and the metal panel for it. No blinky lights of any kind that don't show some status. My initial questions are pretty basic: Any tips or tricks for figuring out whether or not a given component (especially CPU coolers) fit in a modded case? How can I determine how much cooling is required before buying parts, and what is the optimum CPU temp range, anyway? The original PowerMac PSU had a rear mounted fan and blew air out the back of the case. The only example of an ATX PSU I can find like that is suspiciously cheap at <$20. Anyone know of a reliable modular PSU with power location compatible with the Graphite case and with a fan that blows out on the same face of the PSU as the power plug?