my vegas 64 liquid didn't want to go below 875mv (850 in gpu-z) with soc clock 1107 (needed for mem clock 1100). It results in 19.6khs
For 1140 mem clock (1199 soc clock) they need 900mv (875 in gpu-z). It results in 20.2khs

It doesn't depend on gpu clock - only soc clock is setting min required voltage.

vega 56 ref samsung with stock bios is happily mines with 825mv (800 in gpu-z) with 940 mem clock resulting 19.5khs