Lets say this would be an average SoC that would draw 4 watts, I don't think it would be a 10x reduction after removing all the console-only parts. The disk drive as a moving part takes a lot of voltage, the fan, the plethora of ports, let alone charging or powering something from that port, that would already reduce the power quite a bit.
hm... well, the disc drive will be around 5W for constant spin operation. The fan they use is rated up to 2.5W (I imagine that's high RPM/audible noise level though).
33W -> 25W ? So to hit 5W typical operation, that's still down to 20%.
Of course, there is the matter of fab differences and also the specific node design (bulk/SOI, SHP etc), but that's hard to quantify.
I dunno. Colour me skeptical (45nm Renesas to 28nm elsewhere).
Anyways, I suppose there's room to play around depending on what you're thinking for the device size, weight & battery.
iPad Air is roughly 4.6W (
Anandtech 32.4WHr/7.07Hr) during a 3D game. Of course, the screen they use also has an effect there, typically the higher % of total power consumption TBH.
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Consider that the Gamepad's battery was ~5.5WHr (3.7V*1500mAHr) with barely much in the way of processing...
*shrug*
We don't really see how much benefit 28nm parts have over the last two generations of 32 and 45 because most chip makers take that chance to add more transistors to gain performance.
I'm talking more about the actual node transition characteristics. For example, TSMC claims 40% power savings between their 28nm and 40nm processes, but only 25% between 20nm and 28nm. It's slowing down.