Since I referred to the
ITRS roadmap from 2017 earlier, I'll stick with that for consistency. Also, sticking with what TPU lists for consistency. So again, grain of salt with regards to their accuracy.
PS1 to PS2: 600nm to 250nm is two generations by the roadmap (500nm would then be part of the 600nm generation).
PS2 to PS3: 250nm to 65nm is four generations.
Note made after writing the rest of this post: 65nm seemed a little fishy considering that Xbox 360 and Wii are listed at 90nm. Checking with
wiki, 65nm applies for later revisions. The older models with PS2 compatibility were on 90nm. So PS2->PS3 is more like three generations, as far as original design goes.
65nm process nodes would be ~2004-2007. Here's where an important note goes:
Dennard scaling, or MOSFET scaling. Basically the observation of power consumption improvement keeping up with transistor density. That started breaking down in the mid 2000's.
Remember the clock frequency race back then? The dreams of 10 gigahertz and then how those dreams died like Icarus? Then we had the paradigm shift to multi cores? It was around that same time wasn't it...
(the straightforward interpretation: those 2/4 generations back then offered a lot more energy efficiency improvement compared to 2/4 generations now)
PS3 to PS4: 65nm to 32nm is two generations. I'm filing TSMC 28nm under the 32nm generation because their 20nm node started up after PS4's launch. While Dennard scaling has
started its breakdown, we're still in the period where planar transistors are still worth squeezing. So those two generations still offer more potential what we'd see with two nowadays, IMO anyway.
Note made after writing the rest of this post: Alternatively, going from 90nm (first versions of PS3) to 32nm is three generations.
XBox to Xbox 360: Huh, TPU says 150nm? TSMC's own website doesn't mention such a node... I'm guessing a 180nm refinement, as there is a separate 130nm node. Anyway, 180nm to 90nm is two generations.
Xbox 360 to Xbox One: 90nm to 32nm is three generations.
GCN to Wii: 180nm to 90nm is two generations.
Wii to Wii U: 90nm to 45nm is two generations. 45/40 should be within the same generation.
Yaknow, there's more I can ramble on regarding possible future of consoles, but I don't have the time to put it within this post. Sometime later, I might reply to this and go stream of consciousness on the topic. Although it'd be more related to the big consoles than the Switch.