Larian Studios Forums Baldur's Gate III Baldur's Gate III - General Class vs Character Levels and Magic

You can Haste yourself with a potion rather than taking two levels of Fighter for triple Fireball.

Larian also provided a handy Circlet that grants you an extra Bonus Action when you deal fire damage. So you can Fireball + Quicken twice for two more Fireballs without having to use any Haste potions.

Of course Wet + triple Lightning Bolt will be a lot better since it does the damage of 6 Lightning Bolts.