Quote Originally Posted by Opteron146 View Post
Easy answer, because it will be sth like:
[x][x][x]
[x][x][y]

Where y = unknown.
Partly it will be used up by PCIe, maybe they add a directory cache, too, maybe something else ... but you can bet that they wont do anything unnecessarily ;-)
They will prob add an extra module inside [y] to help getting a higher % of working chips during manufacturing. Easier to get 5 out of 6 working then 5 out of 5.

Maybe some nice unlocks in the future if they do it that way too