After some tweaks and overclocking (including this SSDT, v2.3), my GB4 score went up from ~170k to 210k on my (seriously) overclocked Vega 56 (watercooled, custom loop), but only a very slight improve on GB5, from ~59k to ~61k.
Nice! :)
PS: MacPro7,1 SMBIOS! :headbang: