Can you tell me why these builds have wildly different DPS on POB?

https://pobb.in/hjP_-6QbFe59 - this build was put together for me by a really kind community member here. he changed my tree and added a new weapon type and one new skill gem

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i took his advice; fast forward a few weeks to my current account: https://pobb.in/elMsFo06h1lm

i got the weapon type and followed the tree very closely, made some minor changes along the way. my damage and survivability feel great overall (MASSIVE improvement from before i switched to the current build) but i noticed the other day that the original link says 516k dps while my current build is showing 128k.

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I can't for the life of me find anything that would make up that big of a dps different, so im wondering what im missing here or if im just not understanding something about how POB works. Any ideas?