Just wondering if anyone can help me out with this.

Right now I"m an i90 pld and i'm trying to maximize gear (valor and allagan) so I have a good distribution of all stats. Right now my hp is about 6850ish with food. My question is in regards to PLDs with more hp. I will party with some plds who have 6900 or even 7000 and may have a lower ilv then me. I'm just wondering how they're getting those numbers? I know race is a factor but is it really this much?