I understand that PRAM is comparable to PC's CMOS, but the logic board I am replacing did not have this PRAM battery. The logic board I've received does not have it either, but on ifixit's guide it specifies hooking it back up. I looked on the back of the board and it appears that there is a spot for the PRAM battery and there is sticky residue which leads me to believe I need it. So...is the necessary or does the board have some sort of built in feature that will save settings? And is it common for sellers to sell logic boards without this piece? Thanks.