AMD Blender Open Data Benchmark Performance is embarrassing versus Nvidia.
I just took a look at the performance of top end versions of all supported AMD GCN generation GPU on Blender 2.83. with AMD Latest Adrenalin 2020 20.5.1 Driver.
The performance of AMD GPUs on that test suite is embarrassing.
RX Vega 64 Liquid is still faster than RX5700XT.
I compared to a 2 slot (40mm) dual fan Palit RTX 2080 OC at stock clock speed.
Let's just concentrate on the most complex test case in the Blender Test Suite - "Victor".
Nvidia RTX2080 (~ a.k.a RTX2070 Super these days) CUDA performance is much faster than RX Vega 64 Liquid.
Nvidia RTX2080 (~ a.k.a RTX2070 Super these days) OptiX performance extends that lead even further.
Please do not suggest that I run Blender on a 16 core 32 thread Ryzen Processor to attempt to catch up to Nvidia RTX 2080 performance.
I admit I have not tested a Radeon VII. I did try to buy one at launch. Luckily they had none in stock and I got a refund.
The RX Vega 64 Liquid was tested running at the same clock speed and higher HBM2 overclock than a Radeon VII anyhow.
Suggesting I use Radeon ProRender instead is not a serious option.
Lower end, older GPUs such as the RX590 8GB or the formerly top end R9 390X 8GB will not even run the "Victor" benchmark. They freeze at the starting point.
HBCC is not supported on Blender at all. Turning it on with an RX Vega 64 Liquid results in Blender Crash/Freeze.
So AMD - have you just given up on GPU Compute for Blender completely?