This is the best I can do benchmarking wise:
https://www.3dmark.com/fs/14914856
Downcored to "Vega 8" (CU10 - CU8 disabled, 512SP) config.
https://www.3dmark.com/fs/14914919
It is far from stable, just stable enough for benching.
This is on the delidded (and relidded) chip, on AMD Wraith (OG, 125W rated) cooler.
ITX board as well, however the said ITX board happens to have the best VRM of any AM4 boards so far.
Never thought I would say that about an MSI board
CPU 1.4375V, SoC / GPU 1.3000V.
Higher the MEMCLK is, higher the difference between the Vega 8 and Vega 11 configurations is.
At >= 3200MHz MEMCLK there would barely be any difference.