There is a long tradition of serial memory interfaces. RDRAM/XDR DRAM, FB-DIMM/AMB, Intel SMB, OMI DIMM/DDIMM, etc. They seem to have most success in high end

There is a long tradition of serial memory interfaces. RDRAM/XDR DRAM, FB-DIMM/AMB, Intel SMB, OMI DIMM/DDIMM, etc. They seem to have most success in high end server CPUs where memory capacity and throughput are important. They have cost, power, latency disadvantages, so their forays into low end servers, PCs, etc has been more sporadic.