Does mana recharge at the same rate regardless of intelligence ?

Just curious as to how this would work if my mana bar was like 250000 if id's be resting for years to restore it or whether it's percentage based

Also what would be the best method of restoring it if I had the Atronach sign and my intell (and mana) was in the thousands because I used the exploits (cause its fun)

Would absorbing spells be ineffective past a certain point ?

Also let me know if you hate that I'm referring to it as mana and not magicka