Albert Penello
I'm sure there have been lots of interviews about the X1 rollout that cover anything I could say.
Regarding RAM, It's most likely I'm going to take a ton of guff for this, but here goes (it's very similar to what happened on X360 but reverse). The Gen 8 spec was going to be 4GB. That would have been 4x the amount of memory from Gen7 so that was the target for both consoles based on what we knew. With all the Kinect and Media stuff the team knew that would eat too much memory for games and proposed 8gb - 2-3 for media, and 5-6 for games. Once the xbox team had knowledge there was a gap in GPU with PS4, the feeling was that the incremental 1-2 gb for games, while slower, would make up some of the difference. So having say 5-6gb for games in DDR3 could offset having only 3.5gb of GDDR5 (having half the memory would have meant half the memory bandwidth, too).
Once word got out X1 had 8gb (and of course Sony would not have known the type of RAM we were using or for what), we heard that matched to 8. I think that part is pretty undisputed at this point. So that was a bummer for X1 but was a super smart call on Sony's part. Of course, the exact opposite happened on X360.
It would be interesting to think what a 4gb PS4 vs. an 8GB X1 battle would have looked like in games, given their advantage in GPU.