Microsoft's Xbox 360, Sony's PS3 - A Hardware Discussion

The Consoles and their CPUs

The CPUs at the heart of these two consoles are very different in architecture approach, despite sharing some common parts.  The Xbox 360’s CPU, codenamed Xenon, takes a general purpose approach to microprocessor design and implements three general purpose PowerPC cores, meaning they can execute any type of code and will do it relatively well.

The PlayStation 3’s CPU, the Cell processor, pairs a general purpose PowerPC Processing Element (PPE, very similar to one core from Xenon) with 7 working Synergistic Processing Elements (SPEs) that are more specialized hardware designed to execute certain types of code. 

So the comparison between Xenon and Cell really boils down to a comparison between a general purpose microprocessor, and a hybrid of general purpose and specialized hardware. 

Despite what many have said, there is support for Sony’s approach with Cell.  We have discussed, in great detail, the architecture of the Cell processor already but there is industry support for a general purpose + specialized hardware CPU design.  Take note of the following slide from Intel’s Platform 2015 vision for their CPUs by the year 2015:

The use of one or two large general purpose cores combined with specialized hardware and multiple other smaller cores is in Intel’s roadmap for the future, despite their harsh criticism of the Cell processor.  The difference is that Cell appears to be far too early for its time.  By 2015 CPUs may be manufactured on as small as a 32nm process, significantly smaller than today’s 90nm process, meaning that a lot more hardware can be packed into the same amount of space.  In going with a very forward-looking design, the Cell processor architects inevitably had to make sacrifices to deal with the fact that the chip they wanted to design is years ahead of its time for use in general computation.