Help with Weapon Choice

Hello everyone!

I've been trying (unsuccesfully) to figure out which weapon would be a bigger upgrade for me. I'm playing a pure Physical Crossbow-Build.
As far as i can see (with my budget) i can either get a Crossbow with ~900 physical dps, or one with around 800 and "damage gained as extra physical". I assume that the latter would be better, but i wanted to double check before spending quite a lot of currency.
The build is Armour Break > Riven > Frag Rounds, so no other damage type except a little bit of bleed (Herald of Blood) for the clear.
Thanks a bunch!

pob it