Depends. NVLink advertises bidirectional bandwidth, whereas PCIe and standard networking calculate bandwidth in a single direction. So a 1800 GBps NVLink is actually 900 GBps in PCIe and standarding networking terms.
Therefore, a 512 GBps PCIe would sit between the current H100 NVLink (450 GBps) and next generation B200 NVLink (900 GBps). With that being said, NVLink still has lower power draw and smaller chip area, so it would still have a competitive advantage even if the bandwidth is similar.
Therefore, a 512 GBps PCIe would sit between the current H100 NVLink (450 GBps) and next generation B200 NVLink (900 GBps). With that being said, NVLink still has lower power draw and smaller chip area, so it would still have a competitive advantage even if the bandwidth is similar.