@ Tonyyeb
Sorry to have taken over the thread.
@Oliver
I wish I could get two high density FPGA chips on a mATX or standard ATX board for building a new computer.
As far as 4 layer board are concerned, the blind vias, I believe, are electro-plated and have contact pads between boards that dig into each other between each layer( thinktink).
If a board was layered A,B on the first board and C,D on the next board, I could connect A to B and C to D then A to D. Edit: I bet I would have to make sure the two boards were good before I joined them.
What do you think?
I do not know much about signal integrity and noise and other related physics to really be of help.
Good day.