[benlwalker]

I don't have any formal comparisons handy but there's lots of NVMe-oF benchmarks here: https://spdk.io/doc/performance_reports.html

NVMe-oF can do both TCP (akin to iSCSI) and RDMA (akin to iSER). There are likely several reasons NVMe-oF is faster, but one big one is that each connection within a session shares state in iSCSI, so you either process all connections for a session on a single thread or you take locks. In NVMe-oF, it's possible to keep every connection entirely independent, so the NVMe-oF implementations scale better.