With FPGA cards that interfaced with Xeons over PCIe.
There was no modification of the Xeon devices let alone the x86 cores
yet again mr chipguy misses the forest for the trees. so msft chose to use fpga cards over high latency /high power pcie links to implement new computing units even though they had the option to add fpga blocks to their x86 based cpus. how stupid of them.