One of the biggest benefits of switching to Intel processors is that they use less energy and, therefore, generate much less heat than the PowerPC processors Apple was using previously. Less heat produced means less cooling required, so by removing fans and other design elements implemented specifically to keep air flowing, Apple reclaimed a lot of space. Gone are the four separate air-flow conduits of the original G5, as well as the special molded-plastic interior door that kept air flowing even if you removed the G5’s external door. And the two Xeon processors fit beneath a heat sink that’s actually smaller than one of the dual-processor Power Mac G5’s two heat sinks.