It turned out that the original testing of Ivy vs Sandy had been done badly, and that they actually perform very similarly. The difference can be explained away as due to what is known to be different.
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
