I really don't think they decided to use this architecture based on getting BC with the Wii for a rather simple reason... If they wanted, they could just make a whole new architecture and include the Wii hardware, it wouldn't add as much cost as in other consoles because the Wii was outdate and inexpensive hardware at launch.
They used this architecture because Nintendo's and many third party developers are already used to coding for this architecture, which helps decrease time/costs in training developers. Sony's and Microsoft's decision in using PC like hardware also has to do with this architecture being familiar with developers, decreasing the learning curve.
Also, I don't buy the "they invested a great deal of money and time on refining PPC7xx by adding an ARM core for background OS functionality and SIMD which is poor/non-existant on standard PPC7xx, miniaturizing the chip and putting three cores in it" for me this is pure conjecture.
Sony and Microsoft literally went door-to-door when they started designing their systems, they asked developers directly what they expect from a nextgen system and, bizzarely enough, they came up with very similar consoles in terms of the components. This is no coincidence - two huge companies
and competitors in the field ended up with near-twin systems. Developers were
clearly sick and tired of PowerPC - they wanted a system with as little need for microcode as possible, they wanted to focus on programming games, not programming systems to play their games which is why
they chose x86_64.
Espresso is nobody else's but Nintendo's brainchild - call it conjuncture if you will, I have evidence to serve. Take a look at the
PPC7xx family tree - there hasn't been any major developments in it since Broadway, which is
also a Nintendo-exclusive chip. Look at what the article says:
"The 7xx family had its shortcomings, namely lack of SMP support and SIMD capabilities and a relatively weak FPU. Motorola's 74xx range of processors picked up where the 7xx left off."
At the starting point, PPC7xx didn't have SIMD capabilities
at all, they were added per Nintendo's request.
No other CPU's in that tree do any SIMD at all according to the article - only Gekko, Broadway and the Espresso are capable of them. And what about the co-operation and investments I speak of? Let's continue reading from the Gekko article:
"The project was announced in 1999 when IBM and Nintendo agreed to a one billion dollar contract for a CPU running at approximately 400 MHz."
Back before the Gamecube was released, Nintendo pumpled a
billion dollars into IBM to design a chip for them, a chip that would serve their specific needs and IBM did just that - they created the Gekko. The last part of that paragraph is also important - the 74x is the continuation of this family, the 7xx was considered
"done" already in terms of development.
Next came the
Broadway, a direct successor to the Gamecube's Gekko, sharing many similarities and running at a higher clockspeed. Why did they go this way? Because Nintendo already spent lots of money and time on improving the PPC7xx architecture to serve gaming needs and they wanted to continue reaping profits off it.
Finally, we reach the
Espresso, which again is the brainchild of an IBM and Nintendo relationship. Unsurprisingly, the Espresso contains an ARM chip on it - Starbucks, just like Hollywood, Nintendo's and AMD's graphics chip on the Wii contained an ARM chip Starlet. Why? For Wii background operations, just like on the Wii U.
Look at all these
"lucky" coincidences showing that the three processors have much in common, that the PPC7xx family was at this point practically abandoned with Nintendo introducing improvements and keeping it alive over the decades. Why do I say that? Because that's what IBM said - let's head back to the
PPC7xx family tree:
"IBM has ceased to publish a roadmap to the 750 family, in favor of marketing themselves as a custom processor vendor. Given IBM's resources, the 750 core will be produced with new features as long as there is a willing buyer. In particular, IBM has no public plans to produce an ordinary 750-based microprocessor in a process smaller than 90 nm, effectively phasing it out as a commodity chip competitive in such markets as networking equipment."
Let's read that carefuly - IBM ceased to publish a roadmap for the CPU family, they have no plans to produce PPC7xx in a process smaller than 90 nm which effectively means they have no plans of improving it, they effectively phase it out from the market
but they are
willing to produce and improve it as long as there's a willing buyer. What does that tell us?
It tells us that Nintendo specifically requested this and no other processor family - they wanted to stay backwards compatible, they did it by choice, with a three-fold reason - to stay backwards compatible, keep the development environment as similar to the Gamecube's and the Wii's as possilbe and continue to use an architecture they know - an architecture they invested a lot of money into and an architecture that they kept alive to this day.
But alas, this is all conjuncture... right?
Looking at the likes of Dolphin it does require the beefiest PC and I reckon the PS4/Xbone hardware could emulate it well enough. Finesse things a bit with game specific mods or even the source code to the original game...
In other words, take the price of the PS4, add a $100 to it for the gamepad
(or as Nintendo says, a $160 as far as I remember, which is a load of croak, but hey!) aaand... Wii U-ber?
