... the MPW samples, and they aren't FCLGA....
No pictures of chip itself so we don't know. There's no reason that it couldn't be a FCLGA... It's not a big processor with over thousand pins so it dosn't need to look like one....
There are pictures of the chip mounted to the board, as well as the board mounting pattern. While you could do a flip chip like that an encapsulate it, it would seem weird to do so with those massive power and ground pads at the bottom if you're planning on pulling most of the heat out the top. You can get overmolded FC packages, but the thermals out the top aren't usually great.
I will concede it could be FCLGA though.
I'm also curious how friedcat want to achive better performance in mass production chips. As for now we only know that with samples he achieved better specs than simulations. 6GH/s | 0.343w/g vs. 7.2GH/s | 0.2495W/G