See http://www.bloomberg.com/news/articles/2016-06-09/how-intel-makes-a-chip
"If you buy an off-the-shelf Xeon server from Dell or HP, the Xeon inside will contain technology that’s off-limits to you. “We’ll integrate [a cloud customer’s] unique feature into the product, as long as it doesn’t make the die so much bigger that it becomes a cost burden for everyone else,” says [Diane] Bryant. “When we ship it to Customer A, he’ll see it. Customer B has no idea that feature is there.”"