I'm trying to develop a system with Virtualbox that involves streaming uncompressed high resolution video (1440p) from the guest to the host with as close to zero latency as possible. I've been using iperf to measure network bandwidth between the guest and the host with a few different configurations.
Test 1: Host to host, ~40Gbits/s
Test 2: Guest to host, NAT, ~2.5Gbits/s
Test 3: Guest to host, Bridged Adapter, ~20Gbits/s
Test 4: Guest to host, NAT, using settings found here, less than 1Gbits/s
From what I calculated, the task I'm trying to accomplish would require about 5-6 Gbits/s. All of the configurations I've tried with the NAT adapter don't have enough bandwidth, and the Bridged Adapter is not ideal because it introduces a lot of extra latency by going through physical networking hardware. I don't really understand why the NAT adapter can't run at speeds similar to the localhost loopback on the host machine. I'm not very experienced with low level networking and I've searched all over the web for a solution.
TL;DR: Does anyone know how I can achieve a high bandwidth connection from the guest to the host without using a bridged adapter?