Did you actually measure vgpu and vram after and before modding? Generally there are cards out there not benefiting from volt mods whatsoever... but you will definitely see gains from switching to watercooling. I wonder why your temps are this low considering all the peeps claiming overheating cards or temps in the high 80s to low 90s when pushing those cards.

BTW, there were infos from the German (European) Subsidiary that all (most?!) of the vanilla cards should be already factory-modded to 1.2Vgpu... Wonder if this is the truth.