Z170 will not help with multitasking.
The main help comes from more ram.
H110 will support up to 32gb because it only has 2 ram slots.
https://en.wikipedia.org/wiki/LGA_1151
If you think you need 64gb, then a different chipset would be required.
A i7-6700 or i5-6500 work equally well on H110.
Actually, a I7 6700K will be faster than the base i7-6700 because it has higher base clocks. (4.0 vs 3.4 for the 6700)
Considering the relatively small price difference, I would go that way, even if you will not overclock.