Assuming that i have all the perks for that category of weapons, and for the enchanted unique weapons.

A wild guess would be the Chillrend...?

According to uesp, its tied with the dragonbone sword (dawnguard) for highest base damage. Both have 15 base damage but since chillrend is lighter it'll have the higher DPS. Make sure you wait till you're lvl 46 though or you'll get a weaker version of chillred w/ lower base damage.

Every sword has same speed. Weigh does not factor into this. Weigh is used to calculate Stamina usage though, AFAIK.