How is the mana regain rate calculate

[MZ3K]

Anyone know how the mana regain rate is calculated?
I heard that there's a disproportional boost to the regain rate at 100 and a boost for chars with 100 int. Is that true?

 

[Experience]

AFAIK the higher your intel (in 20 point increments i think) gives you a boost as well as Meditation bonus