Firingsquad takes a look at the top mistakes Microsoft made with the Xbox 360 console:
Mistake #1: Overheating CPU or GPU
Anyone could have seen this one coming. With today's high performance GPUs and multi-core CPUs drawing more and more power, thermal management has become a critical element of modern systems. In the Xbox 360, either the GPU or the CPU is to blame for most of the overheating problems. As our esteemed colleague and FiringSquad alum, Tuan Nguyen showed, the bulk of the Xbox 360's heatsinks are focused on cooling the IBM PowerPC CPU. This either means that the PowerPC runs too hot and needs all that cooling, or that the GPU is not being cooled well enough. Although there were initial rumors of the power supply overheating, we can find no evidence to support this claim other than the repeated story of "holding the power supply up by a string." It's either the CPU or the GPU’s fault.