Thanks for the reply - I probably shouldn't have deleted my actual full question.
I was actually asking if it mattered if I boiled my whole water amount instead of partial. The kit I was using was a "non-boil" kit that called for boiling 2 gallons & adding the kit to that, then topping off the rest of the water- but I wanted to boil all 5 & then cool before pitching because my tap water isn't the best. I went ahead with boiling all 5 gallons and everything turned out ok. She's fermenting away nicely right about now.