I know, weird question, but i've recently been into underclocking my 1070s and 1070TIs to about 70% power limit and overclocking core clock +99 and memory clock +~800, anyways, will this damage the card to deprive it of power at the same time i increase the core clock and memory clock?
PS: yes it's stable, these new 1070 cards are amazing.
I think you mean undervolting and not undercloking since you are overcloking the rest of your card, As long as your card is 100% stable and have a good security marging you shoudn't have any issues, in fact the opposite since the cards will heat less and the electrical resistance is lower.
As for underclocking as the other mentioned previously it's only positives aside less performance.