A good way to work out whether this is a GPU bound spot would be to look at the difference between 1xIR and 2xIR (and if you could be bothered to hack it in to a recent build 0.5xIR).
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
