Third level spells are where mages start pulling their own weight in AD&D 2nd ed. They get tricky at fifth though, because the new cone of cold spells 1d4+1/level yields the same average damage as fireball and lightning bolts 1d6/level—but the latter pair is capped at 10d6, while cone of cold keeps giving 1d4+1/level forever, making it better on average when the mage hits eleventh level, and by thirteenth level the max damage is higher, too.