Found a way to lower my GPU mem clock from constant boosting, but I am not sure what it does (Custom Resolution Utility, CRU)

hey,

so I found a way to lower my mem boost clock on my 4070 ti from chronic boosting to much lower by following a youtube guide, it seems to work well, however the guide does not explain what it actually does.

I increased my Vertical Blanking to 50, but what does it actually do? I have tried googling it but I cant seem to find any answers.