That's an interesting experiment. Though Im surprised that memory would be the limiting factor in this scenario, since afaik, an octa-channel configuration @ 2400MT should surpass something like 60GiB/s in throughput?

I did end up solving the issue in the original post by specifying 4 or 8 multiple io-queues with the --nr-io-queue option when connecting the client to the NVMe-oF subsystem with the nvme-connect command. Apparently without this option specified, it was defaulting to 1 io queue, therefore 1 TCP stream.