> With eight octa-core compute dies, Rome can offer up to 64 cores and 128 threads, effectively doubling/quadrupling (AVX2) the throughput of first-generation EPYC. Although Rome stays with 128 PCIe lanes, it brings new supports for PCIe Gen 4, doubling the transfer rate from 8 GT/s to 16 GT/s. There are eight DDR4 memory channels supporting up to four terabytes of DRAM per socket. One interesting detail AMD disclosed with their GPU announcement is that the infinity fabric now supports 100 GB/s (BiDir) per link. If we assume the Infinity Fabric 2 still uses 16 differential pairs as with first-generation IF, it would mean the IF 2 now operates at 25 GT/s, identical to NVLink 2.0 data rate. However, since AMD’s IF is twice as wide, it provides twice the bandwidth per link over Nvidia’s NVLink.

https://fuse.wikichip.org/news/1815/amd-discloses-initial-zen-2-details/