Quite alot, considering that the dwarf will have trouble maxing haste boost and extra boosts. Spending 12 APs on the DAs is very expensive.
Assuming that the dwarf somehow manages to free 13 APs to max haste boost and extra boost from non-dps enhancements the difference will be around 24 DPS. 319 fo the dwarf VS 343 for the human.
If the dwarf stays with rank II haste boost it will be down at 299 DPS.
Compare that to:
Pure dwarven TWF barb: 394,9 DPS(takes 4d3 selfdamage every swing)
And you'll see that it's actually pretty decent DPS for a non-monksplash fullplate character with very high AC.