It is precisely because Intel has developed its own next generation buses, and is licencing them very restrictively, that CAPI exists. Intel has QPI (Quickpath) for internal and Omnipath for external.
nVidia would have loved to have a GPU with a QPI interconnect, but Intel wouldn't let them because they have their own GPU ambitions in Xeon Phi. So they came up with NvLink, which is kind-of PCIe but faster. They don't have any switch asics as yet so they are limited to fully connected topologies. Details on NvLink (without NDA) are scant, but I don't think it has the ability to be multi-node (it really is a bus).
Intel are now making Xeon Phi with on board Omnipath (more like Infiniband), which is curious.
nVidia would have loved to have a GPU with a QPI interconnect, but Intel wouldn't let them because they have their own GPU ambitions in Xeon Phi. So they came up with NvLink, which is kind-of PCIe but faster. They don't have any switch asics as yet so they are limited to fully connected topologies. Details on NvLink (without NDA) are scant, but I don't think it has the ability to be multi-node (it really is a bus).
Intel are now making Xeon Phi with on board Omnipath (more like Infiniband), which is curious.