Article confirms 1 GB of usable RAM for games.
Yep (
1,
2, and more)
This is in part why i was never specific about the memory amount, because devs were working with 1GB for their games, but haven't seen a retail unit with the final quantity of RAM, they were just warned of it.
And there is all this story about the room reserved for the "OS"/Software layer elaborated in many posts like
here.
Nintendo surely got a better idea of the OS size now, the files that constitutes it. But let's say it takes 50mo. It's very likely, considering there was a huge space apparently dedicated to those functions this year, that it will still need an additional room for the Wii U services, background applications, multi-tasking, etc.
So there are two reasons why the system can't have only 1GB of total ram:
1) Studios already built their games with this amount. Imagine Nintendo saying "hey, our OS is 70MB and we need roughly 150mb of memory available while someone plays, so your projects will run with 850MB in the end". It would be a hell, especially for titles who are at roughly 30 fps and who will therefore see their performance decreasing.
Besides:
A: I doubt they found a way to reduce the imprint of all the non-gaming stuff, acknowledging what kind of features (social, internet, multi-tasking, apps, voice chat, camera, etc.) the Wii U is capable of, to a point they would only require let's say 0,1GB in addition to those 1GB. But it's a possibility.
B: I also question the convenience and cheap aspect of the hypothetic choice to integrate a 0,1 to 0,4GB memory chip for the "OS", or design a 1,1GB unified memory chip for games + "OS", rather than simply put 1,5GB.
So to summarize, at worst case scenario, the Wii U got those 1GB granted to developers + an additional X amount for the "software layer".
2) Like i said, some third-parties were noticed at a time, of the normally planned final amount of memory in the retail unit. And it was clearly more than 1GB, more than 1,1GB. But it was a few months ago, long before the OS was completed (if it's the case now), long before the presentation of miiverse and the possible introduction of the dashboard and all this operating system layer to developers. Those developers didn't saw a working commercialized system with its total ram. So we'll need to patiently wait the platform release to finally witness what Nintendo decided on that matter (a weird 1,1GB total quantity or 1,5GB-2GB one).
TLDR: Wii U will rocks, it's a solid and balanced system !