What is Apple's problem?
During the honeymoon between Intel and Apple, Apple release Mac Pros with Xeon's not released officially.
Then Intel/Apple had a fallout over that Intel didn't license the CPU interconnect to Nvidia, so Nvidia was forced stop making motherboards.
Apple started to talk to AMD.
During the Intel/Apple exclusive agreement, Intel engineers designed Apples motherboards. I don't know how its today.
But if Intel still designs Apples...