You definitely need to do the powerplay if you are concerned with powerdraw. Otherwise it mostly even does not matter what voltages you set manually.
You cant get much more than 1950 out of them. I havent seen a reliable way to up the SOC clock with out significantly increasing powerdraw.
You can get 2080h with 1400mhz core / 1199mhz SoC / 1199mhz HBM with a 30%/50w increase in powerdraw. With some mods the cards would crash instantly without core @ 950mv. On some it will work with <900mv settings but it still actually draws 950mv.
I found that the extra 130h @ 50w and much higher temps are not worth it for me.
I know RednoWs reg worked on some cards with high SoC and low voltage but on most cards it will not work and I cant figure out what makes it work on some and not others....
Maybe silicon lottery...