Before you comment about what a noob I am and how I should just get a ATX case, I am well aware that a Powermac G4 needs some serious modding in order to accommodate any other board, be it Micro-ATX or otherwise, and I am willing to do that. What I wanted to know was whether a standard ATX board (not Micro ATX) would fit. In all the other mods I've looked at, people have used Micro ATX, but it is physically possible to put an normal ATX board in there? Also, heatsink fans and the like hitting the PSU shouldn't be problem as I intend to liquid cool it using an external system. Are there any other reasons why a full size ATX mobo would work (such as I/O ports etc...) Mind you, I don't think that those would cause a serious problem as you have to completely cut out the back panel anyway. EDIT: Almost forgot, not using this for a Hackintosh, so it's perfectly legal Thanks.