There is also a stop on the Intel ring bus design for the IMC. Granted, it's a required standard, but it still counts. If memory serves, the single biggest ring that I have seen from Intel was on one of their past Xeon V4 products which I believe was 12 cores, one memory controller, a PCI root, two ring interconnect stations and one space for the external QPI link station. The single ring has been proven to allow 17 stations and a hugher speed, dual ring should be good to at least 17 and likely 20. On a typical client cpu, that's one pci root, one memory controller, one iGPU and up to 14-17 cores/quads. This means that 8 cores and 4 quads is no sweat, and going to 4 more quads isn't outlandish. 8 P cores and 32 e cores would be a MT monster.