Why does Disintegrate deal more damage than Ray of Frost?

I just tested this ingame and i'm definitely getting bigger numbers for Ray of Frost. Monsters die faster because disintegrate hits many of them, but the numbers are smaller.

There must have been some other circumstance that changed in your tests, or there's some kind of passive effect only affecting one of them.

Disintegrate deals more damage overall over Ray of Frost due to the fact that it ramps up DPS as you channel, reaching 890% weapon damage, which is far more than Ray of Frost.